Network Working Group                                      S. Nandakumar
Internet-Draft                                               C. Jennings
Intended status: Informational                                     Cisco
Expires: September 18, 2016                               March 17, January 8, 2017                                    July 7, 2016

                           SDP for the WebRTC
                        draft-ietf-rtcweb-sdp-01
                        draft-ietf-rtcweb-sdp-02

Abstract

   The Web Real-Time Communication [WebRTC] working group is charged to
   provide protocol support for direct interactive rich communication
   using audio, video and data between two peers' web browsers.  With in
   the WebRTC framework, Session Description protocol (SDP) [RFC4566] is
   used for negotiating session capabilities between the peers.  Such a
   negotiation happens based on the SDP Offer/Answer exchange mechanism
   described in [RFC3264].

   This document provides an informational reference in describing the
   role of SDP and the Offer/Answer exchange mechanism for the most
   common WebRTC use-cases.

   This SDP examples provided in this document is still a work in
   progress, but it aims to align closest to the evolving standards
   work.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 18, 2016. January 8, 2017.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  SDP and the WebRTC  . . . . . . . . . . . . . . . . . . . . .   3
   4.  Offer/Answer and the WebRTC . . . . . . . . . . . . . . . . .   5
   5.  WebRTC Session Description Examples . . . . . . . . . . . . .   6
     5.1.  Some Conventions  . . . . . . . . . . . . . . . . . . . .   7
     5.2.  Basic Examples  . . . . . . . . . . . . . . . . . . . . .   8   9
       5.2.1.  Audio Only Session  . . . . . . . . . . . . . . . . .   8   9
       5.2.2.  Audio/Video Session . . . . . . . . . . . . . . . . .  11  12
       5.2.3.  Data Only Session . . . . . . . . . . . . . . . . . .  16  17
       5.2.4.  Audio Call On Hold  . . . . . . . . . . . . . . . . .  19
       5.2.5.  Audio with DTMF Session . . . . . . . . . . . . . . .  23  22
       5.2.6.  One Way Audio/Video Session - Document Camera . . . .  27  26
       5.2.7.  Audio, Video Session with BUNDLE Support Unknown  . .  31  30
       5.2.8.  Audio, Video and Data Session . . . . . . . . . . . .  38  35
       5.2.9.  Audio, Video Session with BUNDLE Unsupported  . . . .  43  40
       5.2.10. Audio, Video BUNDLED, but Data (Not BUNDLED)  . . . .  47  45
       5.2.11. Audio Only, Add Video to BUNDLE . . . . . . . . . . .  52  50
     5.3.  MultiResolution, RTX, FEC Examples  . . . . . . . . . . .  59  57
       5.3.1.  Sendonly Simulcast Session with 2 cameras and 2
               encodings     per camera  . . . . . . . . . . . . . .  59  57
       5.3.2.  Successful SVC Video Session  . . . . . . . . . . . .  66  64
       5.3.3.  Successful Simulcast Video Session with
               Retransmission  . . . . . . . . . . . . . . . . . . .  71  69
       5.3.4.  Successful 1-way Simulcast Session with 2 resolutions
               and         RTX - One resolution rejected . . . . . .  76  74
       5.3.5.  Simulcast Video Session with Forward Error Correction  80  79
     5.4.  Others  . . . . . . . . . . . . . . . . . . . . . . . . .  85  84
       5.4.1.  Audio Session - Voice Activity Detection  . . . . . .  85  84
       5.4.2.  Audio Conference - Voice Activity Detection . . . . .  88  87
       5.4.3.  Successful legacy Interop Fallback with bundle-only .  92  90
       5.4.4.  Legacy Interop with RTP/AVP profile . . . . . . . . .  96  95
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . 101 100
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 101 100
   8.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . . 101 100
   9.  Informative References  . . . . . . . . . . . . . . . . . . . 103 102
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 107

1.  Introduction

   Javascript Session Exchange Protocol(JSEP) [I-D.ietf-rtcweb-jsep]
   specifies a generic protocol needed to generate [RFC3264] Offers and
   Answers negotiated between the WebRTC peers for setting up, updating
   and tearing down a WebRTC session.  For this purpose, SDP is used to
   construct [RFC3264] Offers/Answers for describing (media and non-
   media) streams as appropriate for the recipients of the session
   description to participate in the session.

   The remainder of this document is organized as follows: Sections 3
   and 4 provides an overview of SDP and the Offer/Answer exchange
   mechanism.  Section 5 provides sample SDP generated for the most
   common WebRTC use-cases.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
   "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
   interpreted as described in [RFC2119].

3.  SDP and the WebRTC

   The purpose of this section is to provide a general overview of SDP
   and its components.  For a more in-depth understanding, the readers
   are advised to refer to [RFC4566].

   The Session Description Protocol (SDP) [RFC4566] describes multimedia
   sessions, which can contain audio, video, whiteboard, fax, modem, and
   other streams.  SDP provides a general purpose, standard
   representation to describe various aspects of multimedia session such
   as media capabilities, transport addresses and related metadata in a
   transport agnostic manner, for the purposes of session announcement,
   session invitation and parameter negotiation.

   As of today SDP is widely used in the context of Session Initiation
   Protocol [RFC3261], Real-time Transport Protocol [RFC3550] and Real-
   time Streaming Protocol applications [RFC2326].

   Below figure introduces high-level breakup of SDP into components
   that semantically describe a multimedia session, in our case, a
   WebRTC session [WebRTC].  It by no means captures everything about
   SDP and hence, should be used for informational purposes only.

                                                 +---------------------+
                                                 |        v=           |
                                                 +---------------------+
                 +---------------------+         +---------------------+
         ====    |   Session Metadata  |  =====  |        o=           |
         |       +---------------------+         +----------------------
         |                                       +---------------------+
         |                                       |        t=           |
         |                                       +---------------------+
         |
         |
         |                                       +---------------------+
         |                                       |        c=           |
         |                                       +---------------------+
         |       +---------------------+
         ====    | Network Description |   =====
         |       +---------------------+
         |                                       +---------------------+
         |                                       |    a=candidate      |
         |                                       +---------------------+
         |
         |
         |                                       +---------------------+
         |                                       |        m=           |
         |                                       +---------------------+
         |        +---------------------+        +---------------------+
         ====     | Stream Description  |  ===== |      a=rtpmap       |
         |        +---------------------+        +----------------------
         |                                       +---------------------+
         |                                       |      a=fmtp         |
         |                                       +---------------------+
         |                                       +---------------------+
         |                                       |      a=sendrecv..   |
         |                                       +---------------------+
 +---------------+
 |    SEMANTIC   |
 | COMPONENTS OF |
 |     SDP       |
 +---------------+
         |                                       +---------------------+
         |                                       |      a=crypto       |
         |                                       +---------------------+
         |         +---------------------+       +---------------------+
         ====      |Security Descriptions|  =====|      a=ice-frag     |
         |         +---------------------+       +----------------------
         |                                       +---------------------+
         |                                       |      a=ice-pwd      |
         |                                       +---------------------+
         |                                       +---------------------+
         |                                       |     a=fingerprint   |
         |                                       +---------------------+
         |
         |
         |
         |                                       +---------------------+
         |                                       |      a=rtcp-fb      |
         |                                       +---------------------+
         |         +---------------------+       +---------------------+
         ====      |   Qos,Grouping      |       |                     |
                   |   Descriptions      |  =====|       a=group       |
                   +---------------------+       +----------------------
                                                 +---------------------+
                                                 |       a=rtcpmux     |
                                                 +---------------------+

                   Figure 1: Semantic Components of SDP

   [WebRTC] proposes JavaScript application to fully specify and control
   the signaling plane of a multimedia session as described in the JSEP
   specification [I-D.ietf-rtcweb-jsep].  JSEP provides mechanisms to
   create session characterization and media definition information to
   conduct the session based on SDP exchanges.

   In this context, SDP serves two purposes:

   1.  Provide grammatical structure syntactically.

   2.  Semantically convey participant's intention and capabilities
       required to successfully negotiate a session.

4.  Offer/Answer and the WebRTC

   This section introduces SDP Offer/Answer Exchange mechanism mandated
   by WebRTC for negotiating session capabilities while setting up,
   updating and tearing down a WebRTC session.  This section is
   intentionally brief in nature and interested readers are recommended
   to refer [RFC3264] for specific details on the protocol operation.

   The Offer/Answer [RFC3264] model specifies rule for the bilateral
   exchange of Session Description Protocol (SDP) messages for creation
   of multimedia streams.  It defines protocol with involved
   participants exchanging desired session characteristics from each
   others perspective constructed as SDP to negotiate the session
   between them.

   In the most basic form,the protocol operation begins by one of the
   participants sending an initial SDP Offer describing its intent to
   start a multimedia communication session.  The participant receiving
   the offer MAY generate an SDP Answer accepting the offer or it MAY
   reject the offer.  If the session is accepted the Offer/Answer model
   guarantees a common view of the multimedia session between the
   participants.

   At any time, either participant MAY generate a new SDP offer that
   updates the session in progress.

   With in the context of WebRTC, the Offer/Answer model defines the
   state-machinery for WebRTC peers to negotiate session descriptions
   between them during the initial setup stages as well as for eventual
   session updates.  Javascript Session Establishment Protocol
   specification [I-D.ietf-rtcweb-jsep] for WebRTC provides the
   mechanism for generating [RFC3264] SDP Offers and Answers in order
   for both sides of the session to agree upon details such as list of
   media formats to be sent/received, bandwidth information, crypto
   parameters, transport parameters, for example.

5.  WebRTC Session Description Examples

   A typical web based real-time multimedia communication session can be
   characterized as below:

   o  It has zero or more Audio only, Video only or Audio/Video RTP
      Sessions,

   o  MAY contain zero or more non-media data sessions,

   o  All the sessions are secured with DTLS-SRTP,

   o  Supports NAT traversal using ICE mechanism,

   o  Provides RTCP based feedback mechanisms,

   o  Sessions can be over IPv4-only, IPv6-only, dual-stack based
      clients.

5.1.  Some Conventions

   The examples given in this document follow the conventions listed
   below:

   o  In all the examples, Alice and Bob are assumed to be the WebRTC
      peers.

   o  [I-D.ietf-mmusic-sdp-bundle-negotiation]  It is assumed that for most of the examples, the support for multiplexing
      several media streams over a single underlying transport
      [I-D.ietf-mmusic-sdp-bundle-negotiation] is
      assumed by default established apriori
      either out-of-band or as a consequence of successful Offer/Answer
      negotiation between Alice and Bob, unless explicitly specified stated
      otherwise.

   o  Call-flow diagrams that accompany the use-cases capture only the
      prominent aspects of the system behavior and intentionally is not
      detailed to improve readability.

   o  Eventhough the call-flow diagrams shows SDP being exchanged
      between the parties, it doesn't represent the only way an WebRTC
      setup is expected to work.  Other approaches may involve WebRTC
      applications to exchange the media setup information via non-SDP
      mechanisms as long as they confirm to the [I-D.ietf-rtcweb-jsep]
      API specification.

   o  The SDP examples deviate from actual on-the-wire SDP notation in
      several ways.  This is done to facilitate readability and to
      conform to the restrictions imposed by the RFC formatting rules.

      *  Visual markers/Empty lines in any SDP example are inserted to
         make functional divisions in the SDP clearer, and are not
         actually part of the SDP syntax.

      *  Any SDP line that is indented (compared to the initial line in
         the SDP block) is a continuation of the preceding line.  The
         line break and indent are to be interpreted as a single space
         character.

      *  Empty lines in any SDP example are inserted to make functional
         divisions in the SDP clearer, and are not actually part of the
         SDP syntax.

      *  Excepting the above two conventions, line endings are to be
         interpreted as <CR><LF> pairs (that is, an ASCII 13 followed by
         an ASCII 10).

   o  Against each SDP line, pointers to the appropriate RFCs are
      provided for further informational reference.  Also an attempt has
      been made to provide explanatory notes to enable better
      understanding of the SDP usage, wherever appropriate.

   o  Following SDP details are common across all the use-cases defined
      in this document unless mentioned otherwise.

      *  DTLS fingerprint for SRTP (a=fingerprint)

      *  RTP/RTCP Multiplexing (a=rtcp-mux)

      *  RTCP Feedback support (a=rtcp-fb)

      *  Host and server-reflexive candidate lines (a=candidate)

      *  SRTP Setup framework parameters (a=setup)

      *  RTCP attribute (a=rtcp)

      *  RTP header extension indicating audio-levels from client to the
         mixer

      For more specific details, readers are recommended to must refer to [I-D.ietf-rtcweb-jsep]
      specification.

   o  The term "Session" is used rather loosely in this document to
      refer to either a "Communication Session" or a "RTP Session" or a
      "RTP Stream" depending on the context.

   o  Payload type 109 is usually used for OPUS, 0 for PCMU, 8 for PCMA,
      99 for H.264 and 120 for VP8 in most of the examples to maintain
      uniformity.

   o  The IP Address:Port combinations '192.168.1.4:61665' (host) and
      '24.23.204.141:54609' (Server Reflexive) is typically used for
      Alice.

   o  The IP Address:Port combinations '192.168.1.7:51556' (host) and
      '98.248.92.77:49203' (Server Reflexive) is typically used for Bob.

   o  SSRC cname 'cname:EocUG1f0fcg/yvY7' applies to Alice and the cname
      'cname:Q/NWs1ao1HmN4Xa5' corresponds to Bob.

   o  The SSRCs values '12345', '56789' and '11111' till '66666' usually
      represent Alice's RTP Streams and the values '54321', '98765' and
      '77777' till '99999' represent Bob's RTP Streams.

   o  In the actual use the values that represent SSRCs, ICE candidate
      foundations, WebRTC Mediastream and MediaStreamTrack Ids shall be
      much larger and and/or random than the ones shown in the examples.

      [OPEN ISSUE-1]: SDP Examples for Data Channel, Simulcast, SVC are
      still being discussed and doesn't represent the final solution.

5.2.  Basic Examples

5.2.1.  Audio Only Session

   This common scenario shows SDP for secure two-way audio session with
   Alice offering Opus, PCMU, PCMA and Bob accepting all the offered
   audio codecs.

           2-Way Audio Only Session

   Alice                                Bob
   |                                     |
   |                                     |
   |    Offer(Audio:Opus,PCMU,PCMA)      |
   |------------------------------------>|
   |                                     |
   |                                     |
   |   Answer(Audio:Opus,PCMU,PCMA)      |
   |<------------------------------------|
   |                                     |
   |                                     |
   |Two-way Opus Audio (preferred-codec) |
   |.....................................|
   |                                     |
   |                                     |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma a=group:BUNDLE audio              | [I-D.ietf-mmusic-msid] [I-D.ietf-mmusic-sdp-bundle-n |
   | a=group:BUNDLE audio                                   | [I-D.ietf-mmusic-sdp-bundle-ne egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 8                           |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:60065 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264] - Alice can perform  |
   |                                  | RTP/RTCP Muxing                |
   | a=rtcp:54609 IN IP4              | [RFC3605] - Port for RTCP data send    |
   | 24.23.204.141                                   | and recv audio                |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Opus Codec 48khz, 2 channels  |
   | a=ptime:60                       | [I-D.ietf-payload-rtp-opus] -  |
   |                                  | Opus packetization of 60ms     |
   | a=rtpmap:0 PCMU/8000              | [RFC3551] PCMU Audio Codec    |
   | a=rtpmap:8 PCMA/8000              | [RFC3551] PCMA Audio Codec    |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] Alice supports RTP [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | header extension to indicate [RFC5245] - ICE user fragment |
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | audio levels [RFC5245] - ICE password      |
   | a=sendrecv 74af08a068                        | [RFC3264] - Alice can send and                               |
   | a=fingerprint:sha-256 19:E2:1C:3B | recv audio [RFC5245] - DTLS Fingerprint  |
   | a=setup:actpass :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | for SRTP                      |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               |                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=fingerprint:sha-1 99:41:49:83: a=rtcp-mux                        | [RFC5245] [RFC5761] - DTLS Fingerprint Alice can perform |
   |                                   | RTP/RTCP Muxing               |
   | a=rtcp-rsize                      | [RFC5506] - Alice intends to  |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d                                   | use reduced size RTCP for SRTP     |
   | : 1f:66:79:a8:07                                   | this session                  |
   | a=ice-ufrag:074c6550 a=rtcp-fb:109 nack                | [RFC5245] [RFC5104] - ICE user fragment Indicates NACK    |
   | a=ice-pwd:a28a397a4c3f31747d1ee3                                   | [RFC5245] - ICE password RTCP feedback support         |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464] Alice supports RTP  |
   | hdrext:ssrc-audio-level           | 474af08a068 header extension to indicate  |
   |                                   | a=candidate:0 1 UDP  2122194687 audio levels                  | [RFC5245]
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:12345                      | [RFC5576] - RTP Host Candidate Alice's audio     |
   | 192.168.1.4 54609 typ host cname:EocUG1f0fcg/yvY7            | stream SSRC.                  |
   | a=candidate:0 2 1 UDP  2122194687   | [RFC5245] - RTCP RTP Host          |
   | 192.168.1.4 54609 61665 typ host        | Candidate                     |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245] - RTP Server        |
   | 24.23.204.141 64678 54609 typ srflx     | Reflexive ICE Candidate       |
   | raddr 192.168.1.4 rport 54609 61665     |                               |
   | a=candidate:0 2 UDP  2122194687   | [RFC5245] - RTCP Host         |
   | 192.168.1.4 61667 typ host        | Candidate                     |
   | a=candidate:1 2 UDP  1685987071   | [RFC5245] - RTCP Server       |
   | 24.23.204.141 64678 60065 typ srflx     | Reflexive ICE Candidate       |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104] - Indicates NACK     |
   |                                  | RTCP feedback support          |
   | a=ssrc:12345                     | [RFC5576]                      |
   | cname:EocUG1f0fcg/yvY7           |                                |
   | a=rtcp-rsize                     | [RFC5506] - Alice intends to   |
   |                                  | use reduced size RTCP for this | 61667     |                               | session                        |
   | a=ice-options:trickle a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 1: 5.2.1 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma a=group:BUNDLE audio              | [I-D.ietf-mmusic-msid] [I-D.ietf-mmusic-sdp-bundle-n |
   | a=group:BUNDLE audio                                   | [I-D.ietf-mmusic-sdp-bundle-ne egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 8                           |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtpmap:109 opus/48000/2 a=sendrecv                        | [I-D.ietf-payload-rtp-opus] [RFC3264] - Bob can send and  |
   |                                   | Opus Codec recv audio                    |
   | a=ptime:60 a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   |                                   | Packetization of 60ms Opus Codec                    |
   | a=rtpmap:0 PCMU/8000              | [RFC3551] PCMU Audio Codec    |
   | a=rtpmap:8 PCMA/8000              | [RFC3551] PCMA Audio Codec    |
   | a=extmap:1 urn:ietf:params:rtp-  | [RFC6464] Bob supports audio   |
   | hdrext:ssrc-audio-level a=maxptime:120                    | level RTP header extension as [RFC4566]                     |
   | a=ice-ufrag:05067423              | well [RFC5245] - ICE user fragment |
   | a=sendrecv a=ice-pwd:1747d1ee3474a28a397a4c3 | [RFC3264] [RFC5245] - Bob can send and ICE password      |
   | f3af08a068                        | recv audio parameter                     |
   | a=setup:active a=fingerprint:sha-256 6B:8B:F0:65 | [RFC4145] [RFC5245] - DTLS Fingerprint  |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | for SRTP                      |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               |                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=rtcp-mux                        | [RFC5761] - Bob can perform   |
   |                                   | RTP/RTCP Muxing on port 49203 |
   | a=fingerprint:sha-1 c9:c7:70:9d: a=rtcp-rsize                      | [RFC5245] [RFC5506] - DTLS Fingerprint Bob intends to    |
   | 1f:66:79:a8:07:99:41:49:83:4a:                                   | use reduced size RTCP for SRTP     |
   | 97:0e:1f:ef:6d:f7                                   | this session                  |
   | a=ice-ufrag:05067423 a=rtcp-fb:109 nack                | [RFC5245] [RFC5104] - ICE user fragment Indicates NACK    |
   | a=ice-pwd:1747d1ee3474a28a397a4c                                   | [RFC5245] RTCP feedback support         |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464] Bob supports audio  |
   | hdrext:ssrc-audio-level           | level RTP header extension as |
   |                                   | well                          |
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:54321                      | [RFC5576] - ICE password Bob's audio       |
   | 3f3af08a068 cname:Q/NWs1ao1HmN4Xa5            | parameter stream SSRC.                  |
   | a=candidate:0 1 UDP 2122194687    | [RFC5245] - RTP/RTCP Host ICE |
   | 192.168.1.7 49203 51556 typ host        | Candidate                     |
   | a=candidate:1 1 UDP 1685987071    | [RFC5245] - RTP/RTCP Server   |
   | 98.248.92.77 60654 49203 typ srflx      | Reflexive ICE Candidate       |
   | raddr 192.168.1.7 rport 49203    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104] - Indicates NACK     |
   |                                  | RTCP feedback support          |
   | a=ssrc:54321                     | [RFC5576]                      |
   | cname:NWs1ao1HmN4Xa5/yvY7        |                                |
   | a=rtcp-rsize                     | [RFC5506] - Bob intends to use | 51556     |                               | reduced size RTCP for this     |
   |                                  | session                        |
   | a=ice-options:trickle a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 2: 5.2.1 SDP Answer

5.2.2.  Audio/Video Session

   Alice and Bob establish a two-way audio and video session with Opus
   as the audio codec and H.264 as the video codec.

            2-Way Audio,Video Session

   Alice                                       Bob
   |                                            |
   |                                            |
   |Offer(Audio:Opus,PCMU,PCMA Video:H.264,VP8) |
   |------------------------------------------->|
   |                                            |
   |                                            |
   |      Answer(Audio:Opus,Video:H.264)        |
   |<-------------------------------------------|
   |                                            |
   |                                            |
   |     Two-way Opus Audio, H.264 Video        |
   |............................................|
   |                                            |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 8                           |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264] - Alice can perform  |
   |                                  | RTP/RTCP Muxing                |
   | a=rtcp:54609 IN IP4              | [RFC3605] - Port for RTCP data send    |
   | 24.23.204.141                                   | and recv audio                |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Opus Codec 48khz, 2 channels  |
   | a=ptime:60                       | [I-D.ietf-payload-rtp-opus] -  |
   |                                  | Opus packetization of 60ms     |
   | a=rtpmap:0 PCMU/8000              | [RFC3551] PCMU Audio Codec    |
   | a=rtpmap:8 PCMA/8000              | [RFC3551] PCMA Audio Codec    |
   | a=extmap:1 urn:ietf:params:rtp-  | [RFC6464]                      |
   | hdrext:ssrc-audio-level          |                                |
   | a=sendrecv                       | [RFC3264] - Alice can send and |
   |                                  | recv audio                     |
   | a=setup:actpass                  | [RFC4145] - Alice can perform  | a=maxptime:120                    |                                  | DTLS before Answer arrives [RFC4566]                     |
   | a=ice-ufrag:074c6550              | [RFC5245] - ICE user fragment |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245] - ICE password      |
   | 474af08a068 74af08a068                        | parameter                     |
   | a=fingerprint:sha-1 99:41:49:83: a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245] - DTLS Fingerprint  |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | for SRTP                      |
   | : 1f:66:79:a8:07                 |                                | :04             :BB:05:2F:70:9F:0 | a=candidate:0 1 UDP  2122194687                               | [RFC5245] - RTP Host Candidate
   | 4:A9:0E:05:E9:26:33:E8:70:88:A2   | 192.168.1.4 54609 typ host                               |
   | a=setup:actpass                   | a=candidate:0 2 UDP 2122194687   | [RFC5245] [RFC4145] - RTCP Host Alice can perform |
   | 192.168.1.4 54609 typ host                                   | Candidate DTLS before Answer arrives    |
   | a=candidate:1 1 UDP  1685987071 a=rtcp-mux                        | [RFC5245] [RFC5761] - RTP Server         |
   | 24.23.204.141 64678 typ srflx    | Reflexive ICE Candidate Alice can perform |
   | raddr 192.168.1.4 rport 54609                                   | RTP/RTCP Muxing               |
   | a=candidate:1 2 UDP  1685987071 a=rtcp-rsize                      | [RFC5245] [RFC5506] - RTCP Server Alice intends to  |
   | 24.23.204.141 64678 typ srflx                                   | Reflexive Candidate. use reduced size RTCP for     |
   | raddr 192.168.1.4 rport 54609                                   | this session                  |
   | a=rtcp-fb:109 nack                | [RFC5104] - Indicates NACK    |
   |                                   | RTCP feedback support         |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | hdrext:ssrc-audio-level           |                               |
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:12345                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            |                               |
   | a=rtcp-rsize a=candidate:0 1 UDP  2122194687   | [RFC5506] [RFC5245] - Alice intends to RTP/RTCP Host     |
   | 192.168.1.4 61665 typ host        | use reduced size RTCP for this Candidate                     |
   | a=candidate:1 1 UDP  1685987071   | session [RFC5245] - RTP/RTCP Server   |
   | a=ice-options:trickle 24.23.204.141 54609 typ srflx     | Reflexive ICE Candidate       |
   | raddr 192.168.1.4 rport 61665     |                               |
   | a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Video m=line *********     | ***************************** |
   | m=video 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 99 120                            |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264] - Alice can perform  |
   |                                  | RTP/RTCP Muxing                |
   | a=rtcp:54609 IN IP4              | [RFC3605] - Port for RTCP data send    |
   | 24.23.204.141                                   | and recv video                |
   | a=rtpmap:99 H264/90000            | [RFC3984] - H.264 Video Codec |
   | a=fmtp:99 profile-level- profile-level-id=4d0028 | [RFC3984]                     |
   | id=4d0028;packetization-mode=1 ;packetization-mode=1             |                               |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8] - VP8  |
   |                                   | video codec                   |
   | a=sendrecv a=fingerprint:sha-256 19:E2:1C:3B | [RFC3264] [RFC5245] - Alice can send and DTLS Fingerprint  |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | for SRTP                      |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | recv video                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ice-ufrag:074c6550             | [RFC5245] - ICE user fragment  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=rtcp-mux                        | [RFC5245] [RFC5761] - ICE password Alice can perform |
   | 474af08a068                                   | parameter RTP/RTCP Muxing               |
   | a=fingerprint:sha-1 99:41:49:83: a=rtcp-rsize                      | [RFC5245] [RFC5506] - DTLS Fingerprint Alice intends to  |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:                                   | use reduced size RTCP for SRTP     |
   | 9d:1f:66:79:a8:07                                   | this session                  |
   | a=candidate:0 1 UDP  2122194687 a=rtcp-fb:99 nack                 | [RFC5245] [RFC5104] - RTP Host ICE       |
   | 192.168.1.4 54609 typ host       | Candidate                      |
   | a=candidate:0 2 UDP 2122194687   | [RFC5245] - RTCP Host          |
   | 192.168.1.4 54609 typ host       | Candidate                      |
   | a=candidate:1 1 UDP  1685987071  | [RFC5245] - RTP Server         |
   | 24.23.204.141 64678 typ srflx    | Reflexive ICE Candidate        |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=candidate:1 2 UDP  1685987071  | [RFC5245] - RTCP Server        |
   | 24.23.204.141 64678 typ srflx    | Reflexive Candidate            |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:99 nack                | [RFC5104] - Indicates NACK Indicates NACK    |
   |                                   | RTCP feedback support         |
   | a=rtcp-fb:99 nack pli             | [RFC5104] - Indicates support |
   |                                   | for Picture loss Indication   |
   |                                   | and NACK                      |
   | a=rtcp-fb:99 ccm fir              | [RFC5104] - Full Intra Frame  |
   |                                   | Request-Codec Control Message |
   |                                   | support                       |
   | a=rtcp-fb:120 nack                | [RFC5104] - Indicates NACK    |
   |                                   | RTCP feedback support         |
   | a=rtcp-fb:120 nack pli            | [RFC5104] - Indicates support |
   |                                   | for Picture loss Indication   |
   |                                   | and NACK                      |
   | a=rtcp-fb:120 ccm fir             | [RFC5104] - Full Intra Frame  |
   |                                   | Request-Codec Control Message |
   |                                   | support                       |
   | a=ssrc:1366781083                | [RFC5576]                      |
   | cname:EocUG1f0fcg/yvY7           |                                |
   | a=rtcp-rsize a=extmap:2 urn:ietf:params:rtp-   | [RFC5506] - Alice intends to [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | use reduced size RTCP for this egotiation]                   |
   | a=ssrc:56789                      | session [RFC5576]                     |
   | a=ice-options:trickle cname:EocUG1f0fcg/yvY7            | [I-D.ietf-mmusic-trickle-ice]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 3: 5.2.2 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264] - Bob can perform send and  |
   |                                   | RTP/RTCP Muxing recv audio                    |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Bob accepts only Opus Codec   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:c300d85b              | [RFC5245] -  ICE username     |
   | a=ptime:60                                   | [I-D.ietf-payload-rtp-opus] frag                          |
   | a=sendrecv a=ice-pwd:de4e99bd291c325921d5d47 | [RFC3264] [RFC5245] - Bob can send and ICE password      |
   | efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245] - DTLS Fingerprint  |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | for SRTP                      |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | recv audio                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=ice-ufrag:c300d85b a=rtcp-mux                        | [RFC5245] [RFC5761] -  ICE username frag Bob can perform   |
   | a=ice-pwd:de4e99bd291c325921d5d4                                   | [RFC5245] RTP/RTCP Muxing               |
   | a=rtcp-rsize                      | [RFC5506] - ICE password Bob intends to    |
   | 7efbabd9a2                                   | use reduced size RTCP for     |
   | a=fingerprint:sha-1 99:41:49:83:                                   | [RFC5245] - DTLS Fingerprint this session                  |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=extmap:1 urn:ietf:params:rtp-   | for SRTP [RFC6464]                     |
   | hdrext:ssrc-audio-level           |                               |
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:54321                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 3618095783    | [RFC5245] - RTP/RTCP Host ICE |
   | 192.168.1.7 49203 typ host        | Candidate                     |
   | a=candidate:1 1 UDP 565689203     | [RFC5245] - RTP/RTCP Server   |
   | 98.248.92.77 60065 49203 typ srflx      | Reflexive ICE Candidate       |
   | raddr 192.168.1.7 rport 49203 51556     |                               |
   | a=ssrc:1366788312 a=end-of-candidates               | [RFC5576] [I-D.ietf-mmusic-trickle-ice] |
   | cname:1f0fcgEocUG/yvY7 ****** Video m=line *********     | ***************************** |
   | a=rtcp-rsize                     | [RFC5506] - Bob intends to use |
   |                                  | reduced size RTCP for this     |
   |                                  | session                        |
   | a=ice-options:trickle            | [I-D.ietf-mmusic-trickle-ice]  |
   | m=video 49203 UDP/TLS/RTP/SAVPF m=video 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 99                                |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=sendrecv                        | [RFC3264] - Bob can send and  |
   |                                   | recv video                    |
   | a=rtpmap:99 H264/90000            | [RFC3984] - Bob accepts H.264 |
   |                                   | Video Codec.                  |
   | a=fmtp:99 profile-level- profile-level-id=4d0028 | [RFC3984]                     |
   | id=4d0028;packetization-mode=1 ;packetization-mode=1             |                               |
   | a=rtcp-mux a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5761] [RFC5245] - Bob can perform DTLS Fingerprint  |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | RTP/RTCP Muxing for SRTP                      |
   | a=sendrecv :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [RFC3264] - Bob can send and                               |
   | 1:58:D0:A1:2C:19:08               | recv video                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=ice-ufrag:c300d85b             | [RFC5245] -  ICE username frag |
   | a=ice-pwd:de4e99bd291c325921d5d4 | [RFC5245] - ICE password       |
   | 7efbabd9a2                       |                                |
   | a=fingerprint:sha-1 99:41:49:83: | [RFC5245] - DTLS Fingerprint   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   | for SRTP                       |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP 2113667327 a=rtcp-mux                        | [RFC5245] [RFC5761] - Host ICE Candidate Bob can perform   |
   | 192.168.1.7 49203 typ host                                   | for Opus Stream RTP/RTCP Muxing               |
   | a=candidate:1 1 UDP 1694302207 a=rtcp-rsize                      | [RFC5245] [RFC5506] - Server Reflexive Bob intends to    |
   | 98.248.92.77 60065 typ srflx                                   | ICE Candidate use reduced size RTCP for the above     |
   | raddr 192.168.1.7 rport 49203    | host candidate                                   | this session                  | [RFC5245] - Server Reflexive
   | a=rtcp-fb:99 nack                 |
   | Candidate for the Second Host    |                                |
   | Candidate                        |                                |
   | [RFC5104] - Indicates support | a=rtcp-fb:99 nack pli
   |                                   | for NACK based RTCP feedback  |
   | a=rtcp-fb:99 nack pli             | [RFC5104] - Indicates support | a=rtcp-fb:99 ccm fir
   |                                   | for Picture loss Indication and   |
   |                                   | and NACK                      |
   | a=rtcp-fb:99 ccm fir              | [RFC5104] - Full Intra Frame  | a=ssrc:3229706345
   |                                   | Request- Codec Control Message        | cname:Q/NWs1ao1HmN4Xa5
   |                                   | Message support               |
   | a=extmap:2 urn:ietf:params:rtp-   | [RFC5576]                        | a=rtcp-rsize                   |
   | [RFC5506] - Bob intends to use [I-D.ietf-mmusic-sdp-bundle-n | a=ice-options:trickle
   | hdrext:sdes:mid                   | reduced size RTCP for this egotiation]                   |
   | a=ssrc:98765                      | session [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5            | [I-D.ietf-mmusic-trickle-ice]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 4: 5.2.2 SDP Answer

5.2.3.  Data Only Session

   This scenario illustrates SDP negotiated to setup a data-only session
   based on SCTP Data Channel, thus enabling use-cases such as file-
   transfer for example.

         2-Way DataChannel Session

   Alice                            Bob
   |                                 |
   |                                 |
   |                                 |
   |      Offer(DataChannel)         |
   |-------------------------------->|
   |                                 |
   |                                 |
   |      Answer(DataChannel)        |
   |<--------------------------------|
   |                                 |
   |                                 |
   | Two-way SCTP based DataChannel  |
   |.................................|
   |                                 |
   |                                 |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=group:BUNDLE data               | [I-D.ietf-mmusic-sdp-bundle-ne |
   |                                  | gotiation]                     |
   | a=ice-ufrag:074c6550             | [RFC5245] - Session Level ICE  |
   |                                  | parameter                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245] - Session Level ICE [I-D.ietf-mmusic-sdp-bundle-n |
   | 474af08a068                                   | parameter egotiation]                   |
   | a=fingerprint:sha-1 99:41:49:83: a=ice-options:trickle             | [RFC5245] - Session DTLS [I-D.ietf-mmusic-trickle-ice] |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: ****** Application m=line         | Fingerprint for SRTP ***************************** |
   | 9d:1f:66:79:a8:07 *********                         |                               |
   | m=application 56966 DTLS/SCTP 54609 UDP/DTLS/SCTP | [I-D.ietf-rtcweb-data-channel] [I-D.ietf-rtcweb-data-channel |
   | 5000 webrtc-datachannel                | ]                             |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=mid:data                        | [RFC5888]                     |
   | a=sctpmap:5000 webrtc- a=sendrecv                        | [I-D.ietf-mmusic-sctp-sdp] [RFC3264] - Alice can send    |
   | DataChannel                                   | and recv non-media data       |
   | streams=16;label="channel 1"; a=sctp-port:5000                  | [I-D.ietf-mmusic-sctp-sdp]    |
   | subprotocol="chat"; a=max-message-size:100000         | [I-D.ietf-mmusic-sctp-sdp]    |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=sendrecv a=connection:new                  | [RFC3264] [RFC4145]                     |
   | a=ice-ufrag:074c6550              | [RFC5245] - Alice can send and Session Level ICE |
   |                                   | recv non-media data parameter                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245] - Session Level ICE |
   | 74af08a068                        | parameter                     |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245] - Session DTLS      |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | Fingerprint for SRTP          |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 56966 192.168.1.4 61665 typ host        |                               |
   | a=candidate:1 1 UDP 1694302207    | [RFC5245]                     |
   | 24.23.204.141 56966 54609 typ srflx     |                               |
   | raddr 192.168.1.7 192.168.1.4 rport 56966 61665     |                               |
   | a=ice-options:trickle a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 5: 5.2.3 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=group:BUNDLE data               | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | gotiation] ****** Application m=line         | ***************************** |
   | *********                         |                               |
   | m=application 55700 DTLS/SCTP 49203 UDP/DTLS/SCTP | [I-D.ietf-mmusic-sctp-sdp]    |
   | 5000 webrtc-datachannel                |                               |
   | c=IN IP4 98.248.92.771            | [RFC4566]                     |
   | a=mid:data                        | [RFC5888]                     |
   | a=sctpmap:5000 webrtc- a=sendrecv                        | [I-D.ietf-mmusic-sctp-sdp] [RFC3264] - Bob can send and  |
   | DataChannel:5000                                   | recv non-media data           |
   | streams=1;label="channel 1" a=sctp-port:5000                  | [I-D.ietf-mmusic-sctp-sdp]    |
   | ;subprotocol="chat"; a=max-message-size:100000         | [I-D.ietf-mmusic-sctp-sdp]    |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=sendrecv                       | [RFC3264] - Bob can send and   |
   |                                  | recv non-media data            |
   | a=ice-ufrag:c300d85b              | [RFC5245] - Session Level ICE |
   |                                   | username frag                 |
   | a=ice-pwd:de4e99bd291c325921d5d4 a=ice-pwd:de4e99bd291c325921d5d47 | [RFC5245] - Session Level ICE |
   | 7efbabd9a2 efbabd9a2                         | password                      |
   | a=fingerprint:sha-1 99:41:49:83: a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245] - Session DTLS      |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | Fingerprint for SRTP          |
   | : 1f:66:79:a8:07 :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 55700 51556 typ host        |                               |
   | a=candidate:1 1 UDP 1694302207    | [RFC5245]                     |
   | 98.248.92.77 55700 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 55700 51556     |                               |
   | a=ice-options:trickle a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 6: 5.2.3 SDP Answer

5.2.4.  Audio Call On Hold

   Alice calls Bob, but when Bob answers he places Alice on hold by
   setting the SDP direction attribute to a=sendonly a=inactive in the Answer.

              Audio On Hold

   Alice                            Bob
   |                                 |
   |                                 |
   |      Offer(Audio:Opus)          |
   |-------------------------------->|
   |                                 |
   |                                 |
   |  Answer(Audio:Opus,a=sendonly)  Answer(Audio:Opus,a=inactive)  |
   |<--------------------------------|
   |                                 |
   |                                 |
   |      One-way Opus Audio         |
   |.................................|
   |                                 |
   |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma a=group:BUNDLE audio              | [I-D.ietf-mmusic-sdp-bundle-n | [I-D.ietf-mmusic-msid]
   |                                   | a=group:BUNDLE audio egotiation]                   | [I-D.ietf-mmusic-sdp-bundle-ne
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264] - Alice can perform  |
   |                                  | RTP/RTCP Muxing                |
   | a=rtcp:54609 IN IP4              | [RFC3605] - Port for RTCP data send    |
   | 24.23.204.141                                   | and recv audio                |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Opus Codec 48khz, 2 channels  |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245] -  ICE user         |
   |                                   | a=ptime:20 fragment                      | [I-D.ietf-payload-rtp-opus]
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245] -  ICE password     |
   | 74af08a068                        | Opus packetization of 20ms                               |
   | a=sendrecv a=fingerprint:sha-256 19:E2:1C:3B | [RFC3264] [RFC5245] - Alice can send and DTLS Fingerprint  |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | for SRTP                      |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | recv audio                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ice-ufrag:074c6550 a=rtcp-mux                        | [RFC5245] [RFC5761] -  ICE user fragment Alice can perform |
   | a=ice-pwd:a28a397a4c3f31747d1ee3                                   | [RFC5245] -  ICE password RTP/RTCP Muxing               |
   | 474af08a068 a=rtcp-rsize                      | [RFC5506]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=rtcp-fb:109 nack                | [RFC5245] [RFC5104] - DTLS Fingerprint Indicates NACK    |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:                                   | for SRTP RTCP feedback support         |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | hdrext:ssrc-audio-level           |                               |
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   | 9d:1f:66:79:a8:07
   | a=ssrc:12345                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 1 UDP  2113667327   | [RFC5245]                     |
   | 192.168.1.4 54609 typ host       |                                |
   | a=candidate:0 2 UDP 2113667327   | [RFC5245]                      |
   | 192.168.1.4 54609 61665 typ host        |                               |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=candidate:1 2 UDP  1685987071  | [RFC5245]                      |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104] - Indicates NACK     |
   |                                  | RTCP feedback support          |
   | a=ssrc:3229706345                | [RFC5576]                      |
   | cname:Q/NWs1ao1HmN4Xa5           |                                |
   | a=rtcp-rsize 61665     | [RFC5506]                               |
   | a=ice-options:trickle a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 7: 5.2.4 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma a=group:BUNDLE audio              | [I-D.ietf-mmusic-msid] [I-D.ietf-mmusic-sdp-bundle-n |
   | a=group:BUNDLE audio                                   | [I-D.ietf-mmusic-sdp-bundle-ne egotiation]                   |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=inactive                        | [RFC3264] - Bob puts call On  |
   |                                   | Hold                          |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Bob accepts Opus Codec        |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:c300d85b              | [RFC5245] - ICE username frag |
   | a=ptime:20 a=ice-pwd:de4e99bd291c325921d5d47 | [I-D.ietf-payload-rtp-opus] [RFC5245] - ICE password      |
   | a=sendonly efbabd9a2                         | [RFC3264]                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245] - Bob puts call On DTLS Fingerprint  |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | for SRTP                      |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | Hold                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=rtcp-mux                        | [RFC5761] - Bob can perform   |
   |                                   | RTP/RTCP Muxing               |
   | a=ice-ufrag:c300d85b a=rtcp-rsize                      | [RFC5245] - ICE username frag [RFC5506]                     |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     | a=ice-pwd:de4e99bd291c325921d5d4
   | [RFC5245] - ICE password hdrext:ssrc-audio-level           |                               | 7efbabd9a2
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n | a=fingerprint:sha-1 99:41:49:83:
   | [RFC5245] - DTLS Fingerprint hdrext:sdes:mid                   | egotiation]                   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d
   | for SRTP a=ssrc:54321                      | [RFC5576]                     |
   | : 1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2122194687  2113667327   | [RFC5245] - Host candidate    |
   | 192.168.1.7 49203 51556 typ host        |                               |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245] -  Server Reflexive |
   | 98.248.92.77 24.23.204.141 49203 typ srflx     | candidate                     |
   | raddr 192.168.1.7 rport 49203 51556     |                               |
   | a=ssrc:1366781083                | [RFC5576]                      |
   | cname:EocUG1f0fcg/yvY7           |                                |
   | a=rtcp-rsize                     | [RFC5506]                      |
   | a=ice-options:trickle a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 8: 5.2.4 SDP Answer

5.2.5.  Audio with DTMF Session

   In this example, Alice wishes to establish two separate audio
   streams, one for normal audio and the other for telephone-events.
   Alice offers first audio stream with three codecs and the other with
   [RFC2833] tones (for DTMF).  Bob accepts both the audio streams by
   choosing Opus as the audio codec and telephone-event for the other
   stream.

               Audio Session with DTMF

   Alice                                              Bob
   |                                                   |
   |                                                   |
   |                                                   |
   |  Offer(Audio:Opus,PCMU,PCMA Audio:telephone-event)|
   |-------------------------------------------------->|
   |                                                   |
   |                                                   |
   |    Answer(Audio:Opus, Audio:telephone-event)      |
   |<--------------------------------------------------|
   |                                                   |
   |                                                   |
   |   Opus audio stream and telephone-event stream    |
   |...................................................|
   |                                                   |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio dtmf         | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 8                           |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:54609 IN IP4              | [RFC3605] - Port for RTCP data |
   | 24.23.204.141                    |                                |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264] - Alice can perform send    |
   |                                   | RTP/RTCP Muxing and recv audio                |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Opus Codec 48khz, 2 channels  |
   | a=ptime:20                       | [I-D.ietf-payload-rtp-opus] -  |
   |                                  | Opus packetization of 20ms     |
   | a=rtpmap:0 PCMU/8000              | [RFC3551] PCMU Audio Codec    |
   | a=rtpmap:8 PCMA/8000              | [RFC3551] PCMA Audio Codec    |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245] -  ICE user         |
   | a=sendrecv                                   | [RFC3264] fragment                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245] - Alice can send and ICE password      |
   | 74af08a068                        | parameter                     |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245] - DTLS Fingerprint  |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | for SRTP                      |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | recv audio                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ice-ufrag:074c6550 a=rtcp-mux                        | [RFC5245] [RFC5761] -  ICE user fragment Alice can perform |
   | a=ice-pwd:a28a397a4c3f31747d1ee3                                   | [RFC5245] - ICE password RTP/RTCP Muxing               |
   | 474af08a068 a=rtcp-rsize                      | parameter [RFC5506]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=rtcp-fb:109 nack                | [RFC5245] [RFC5104] - DTLS Fingerprint Indicates NACK    |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:                                   | for SRTP RTCP feedback support         |
   | 9d:1f:66:79:a8:07 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=candidate:0 1 UDP  2122194687 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 192.168.1.4 54609 typ host a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=candidate:0 2 UDP 2122194687 hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 192.168.1.4 54609 typ host a=ssrc:12345                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            |                               | a=candidate:1
   | a=candidate:0 1 UDP  1685987071  2122194687   | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609 61665 typ host        |                               |
   | a=candidate:1 2 1 UDP  1685987071   | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104] - Indicates NACK     |
   |                                  | RTCP feedback support          | 61665     | a=ssrc:3229706345                               | [RFC5576]                      |
   | cname:Q/NWs1ao1HmN4Xa5
   | a=end-of-candidates               |
   | a=rtcp-rsize                     | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | a=ice-options:trickle ****** DTMF m=line *********      | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 126                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:dtmf                        | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=rtcp:54609 IN IP4 a=sendonly                        | [RFC3605] [RFC3264] - Port for RTCP data Alice can send    |
   | 24.23.204.141                                   | DTMF Events                   |
   | a=rtpmap:126 telephone- telephone-event/8000 | [RFC2833]                     |
   | event/8000 a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245] - DTLS Fingerprint  |
   | a=sendonly :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | [RFC3264] - Alice can send for SRTP                      |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | DTMF Events                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ice-ufrag:074c6550 a=rtcp-mux                        | [RFC5761]                     | [RFC5245] -  ICE user fragment
   | a=rtcp-rsize                      | [RFC5506]                     | a=ice-pwd:a28a397a4c3f31747d1ee3
   | [RFC5245] a=rtcp-fb:109 nack                | [RFC5104] - ICE password Indicates NACK    |
   | 474af08a068                                   | parameter RTCP feedback support         |
   | a=fingerprint:sha-1 99:41:49:83: a=extmap:2 urn:ietf:params:rtp-   | [RFC5245] - DTLS Fingerprint [I-D.ietf-mmusic-sdp-bundle-n |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d hdrext:sdes:mid                   | for SRTP egotiation]                   |
   | : 1f:66:79:a8:07 a=ssrc:56789                      | [RFC5576]                     |
   | a=candidate:0 1 UDP  2122194687 cname:EocUG1f0fcg/yvY7            | [RFC5245]                               |
   +-----------------------------------+-------------------------------+

                         Table 9: 5.2.5 SDP Offer

   +-----------------------------------+-------------------------------+
   | 192.168.1.4 54609 typ host Answer SDP Contents               | RFC#/Notes                    |
   +-----------------------------------+-------------------------------+
   | a=candidate:0 2 UDP 2122194687 v=0                               | [RFC5245]                      |
   | 192.168.1.4 54609 typ host       |                                |
   | a=candidate:1 1 UDP  1685987071  | [RFC5245]                      |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=candidate:1 2 UDP  1685987071  | [RFC5245]                      |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104] - Indicates NACK     |
   |                                  | RTCP feedback support          |
   | a=ssrc:9032206345                | [RFC5576]                      |
   | cname:L/N9lk1ao1HmN4Xa5          |                                |
   | a=rtcp-rsize                     | [RFC5506]                      |
   | a=ice-options:trickle            | [I-D.ietf-mmusic-trickle-ice]  |
   +----------------------------------+--------------------------------+

                         Table 9: 5.2.5 SDP Offer

   +----------------------------------+--------------------------------+
   | SDP Contents                     | RFC#/Notes                     |
   +----------------------------------+--------------------------------+
   | v=0                              | [RFC4566] [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio dtmf         | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | gotiation] ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=sendrecv                        | [RFC3264] - Bob can send and  |
   |                                   | receive Opus audio            |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Bob accepts Opus Codec        |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:c300d85b              | [RFC5245] -  ICE username     |
   | a=ptime:20                                   | [I-D.ietf-payload-rtp-opus] frag                          |
   | a=sendrecv a=ice-pwd:de4e99bd291c325921d5d47 | [RFC3264] [RFC5245] - Bob can send and  ICE password     |
   | efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245] -  Fingerprint for  |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | SRTP                          |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | receive Opus audio                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=rtcp-mux                        | [RFC5761] - Bob can perform   |
   |                                   | RTP/RTCP Muxing on port 49203 |
   | a=ice-ufrag:c300d85b a=rtcp-rsize                      | [RFC5245] [RFC5506] -  ICE username frag Alice intends to  |
   | a=ice-pwd:de4e99bd291c325921d5d4                                   | [RFC5245] -  ICE password use reduced size RTCP for     |
   | 7efbabd9a2                                   | this session                  |
   | a=fingerprint:sha-1 99:41:49:83: a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     | [RFC5245] -  Fingerprint for
   | hdrext:ssrc-audio-level           | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:                               | SRTP
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | 9d:1f:66:79:a8:07 egotiation]                   |
   | a=ssrc:54321                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2122194687    | [RFC5245]                     |
   | 192.168.1.7 49203 51556 typ host        |                               |
   | a=candidate:1 1 UDP 1685987071    | [RFC5245]                     |
   | 98.248.92.77 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 49203    |                                |
   | a=ssrc:0634322975                | [RFC5576]                      | 51556     | cname:Q/o1HmN4XNWs1aa5                               |
   | a=end-of-candidates               | a=rtcp-rsize                     | [RFC5506] - Alice intends to   |
   |                                  | use reduced size RTCP for this |
   |                                  | session [I-D.ietf-mmusic-trickle-ice] |
   | a=ice-options:trickle ****** DTMF m=line *********      | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 126                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=mid:dtmf a=rtcp:49203 IN IP4 24.23.204.141 | [RFC5888] [RFC3605]                     |
   | a=mid:dtmf                        | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtpmap:126 telephone-          | [RFC2833]                      |
   | event/8000                       |                                |
   | a=recvonly                        | [RFC3264] - Alice can receive |
   |                                   | DTMF events                   |
   | a=setup:active                   | [RFC4145] - Bob carries out    |
   |                                  | DTLS Handshake in parallel     |
   | a=rtcp-mux                       | [RFC5761] - Alice can perform  |
   |                                  | RTP/RTCP Muxing on port 54690  |
   | a=ice-ufrag:c300d85b             | [RFC5245] -  ICE username frag |
   | a=ice-pwd:de4e99bd291c325921d5d4 | [RFC5245] -  ICE password      |
   | 7efbabd9a2 a=rtpmap:126 telephone-event/8000 | [RFC2833]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245] -  Fingerprint for  |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | SRTP                          |
   | : 1f:66:79:a8:07                 | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               | a=candidate:0 1 UDP 2113667327   | [RFC5245]                      |
   | 192.168.1.7 49203 typ host       |                                |
   | a=candidate:1 1 UDP 1694302207   | [RFC5245]                      |
   | 98.248.92.77 49203 typ srflx 1:58:D0:A1:2C:19:08               |                               |
   | raddr 192.168.1.7 rport 49203 a=setup:active                    | [RFC4145] - Bob carries out   |
   | a=ssrc:6345903220                                   | [RFC5576] DTLS Handshake in parallel    |
   | cname:L/k1aN9lo1HmN4Xa5 a=rtcp-mux                        | [RFC5761]                     |
   | a=rtcp-rsize                      | [RFC5506] - Alice Bob intends to    |
   |                                   | use reduced size RTCP for this     |
   |                                   | this session                  |
   | a=ice-options:trickle a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-trickle-ice] [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:98765                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5            |
   +----------------------------------+--------------------------------+                               |
   +-----------------------------------+-------------------------------+

                        Table 10: 5.2.5 SDP Answer

5.2.6.  One Way Audio/Video Session - Document Camera

   In this scenario Alice and Bob engage in a 1 way audio and video
   session with Bob receiving Alice's audio and her presentation slides
   as video stream.

      One Way Audio & Video Session - Document Camera

   Alice                                                 Bob
   |                                                      |
   |                                                      |
   |                                                      |
   |   Alice Offers sendonly audio and video streams.     |
   |  The video stream corresponds to her presentation    |
   |                                                      |
   |           Offer(Audio:Opus, Video: VP8)              |
   |----------------------------------------------------->|
   |                                                      |
   |                                                      |
   |            (Audio:Opus, Video: VP8)                  |
   |<-----------------------------------------------------|
   |                                                      |
   |                                                      |
   |          One-way Opus Audio, VP8 Video               |
   |......................................................|
   |   Bob can hear Alice and see her presentation slides.|
   |                                                      |
   |                                                      |
   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=rtcp:54609 IN IP4 a=sendonly                        | [RFC3605] [RFC3264] - Port for RTCP data Send only audio   |
   | 24.23.204.141                                   | stream                        |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee34 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendonly 74af08a068                        | [RFC3264] - Send only audio                               |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | stream                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ice-ufrag:074c6550 a=rtcp-mux                        | [RFC5245] [RFC5761]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | 474af08a068 a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: hdrext:ssrc-audio-level           |                               |
   | 9d:1f:66:79:a8:07 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=candidate:0 1 UDP  2122194687 hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 24.23.204.141 54609 typ host a=ssrc:12345                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP  2122194687   | [RFC5104] [RFC5245]                     |
   | 24.23.204.141 54609 typ host      |                               |
   | a=rtcp-fb:109 nack               | [RFC5104]                      |
   | a=ssrc:6345903220                | [RFC5576]                      |
   | cname:L/k1aN9lo1HmN4Xa5          |                                |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | a=ice-options:trickle ****** Video m=line *********     | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=video 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=mid:video a=rtcp:54609 IN IP4 24.23.204.141 | [RFC5888] [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=rtcp:54609 IN IP4 a=sendonly                        | [RFC3605] [RFC3264] - Port for RTCP data Send only video   |
   | 24.23.204.141                                   | stream                        |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=content:slides                  | [RFC4796] -Alice's            |
   |                                   | presentation video stream     |
   | a=sendonly a=fingerprint:sha-256 19:E2:1C:3B | [RFC3264] - Send only video [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | stream                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ice-ufrag:074c6550             | [RFC5245]                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068                      |                                |
   | a=fingerprint:sha-1 99:41:49:83: | [RFC5245]                      |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP  2113667327  | [RFC5245]                      |
   | 24.23.204.141 54609 typ host     |                                |
   | a=candidate:0 2 UDP 2113667326 a=rtcp-mux                        | [RFC5104] [RFC5761]                     |
   | 24.23.204.141 54609 typ host a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=ssrc:3429951804 a=extmap:2 urn:ietf:params:rtp-   | [RFC5576] [I-D.ietf-mmusic-sdp-bundle-n |
   | cname:Q/NWs1ao1HmN4Xa5 hdrext:sdes:mid                   | egotiation]                   |
   | a=rtcp-rsize a=ssrc:56789                      | [RFC5506] [RFC5576]                     |
   | a=ice-options:trickle cname:EocUG1f0fcg/yvY7            | [I-D.ietf-mmusic-trickle-ice]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 11: 5.2.6 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 16833 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | gotiation] ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=recvonly                        | [RFC3264] - Receive only      |
   |                                   | audio stream                  |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:c300d85b              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:de4e99bd291c325921d5d47 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=recvonly efbabd9a2                         | [RFC3264] - Receive only audio                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | stream                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:c300d85b a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 a=rtcp-fb:109 nack                | [RFC5245] [RFC5104]                     |
   | 7efbabd9a2 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:54321                      | [RFC5576]                     |
   | : 1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 98.248.92.77 49203 typ host       |                               |
   | a=ssrc:9513429804                | [RFC5576]                      |
   | cname:Q/o1HmNWs1aN4Xa5           |                                | a=end-of-candidates               | a=rtcp-rsize                     | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | a=ice-options:trickle ****** Video m=line *********     | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=recvonly                        | [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=content:slides                  | [RFC4796] [RFC4796]presentation stream  |
   | a=recvonly a=fingerprint:sha-256 6B:8B:F0:65 | [RFC3264] - Receive Only [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | Alice's presentation stream                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:c300d85b             | [RFC5245]                      |
   | a=ice-pwd:de4e99bd291c325921d5d4 | [RFC5245] a=rtcp-rsize                      | [RFC5506]                     | 7efbabd9a2
   | a=rtcp-fb:120 nack                | [RFC5104]                     | a=fingerprint:sha-1 99:41:49:83:
   | [RFC5245] a=rtcp-fb:120 nack pli            | [RFC5104]                     | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     | 9d:1f:66:79:a8:07
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n | a=candidate:0 1 UDP 2113667327
   | [RFC5245] hdrext:sdes:mid                   | egotiation]                   | 98.248.92.77 49203 typ host
   | a=ssrc:98765                      | [RFC5576]                     | a=ssrc:1366781083
   | [RFC5576] cname:Q/NWs1ao1HmN4Xa5            |                               | cname:EocUG1f0fcg/yvY7           |                                |
   | a=rtcp-rsize                     | [RFC5506]                      |
   | a=ice-options:trickle            | [I-D.ietf-mmusic-trickle-ice]  |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                        Table 12: 5.2.6 SDP Answer

5.2.7.  Audio, Video Session with BUNDLE Support Unknown

   In this example, since Alice is unsure of the Bob's support of the
   BUNDLE framework, following 3 step procedures steps are performed in order to negotiate
   and setup a BUNDLE Address for the session

   o  An SDP Offer, in which the Alice assigns unique addresses to each
      "m=" line in the BUNDLE group, and requests the Answerer to select
      the Offerer's BUNDLE address.

   o  An SDP Answer, in which the Bob indicates its support for BUNDLE,
      and assigns
      selects the offerer's BUNDLE address, selects its own BUNDLE
      address for the and associates it with each BUNDLED m= lines.

   o  A subsequent SDP Offer from Alice, which is used to perform m=line within the
      BUNDLE
      Address Synchronization (BAS). group.

   Once the Offer/Answer exchange completes, both Alice and Bob each end
   up using single RTP Session for both the Media Streams.

    Two-Way Secure Audio,Video with BUNDLE support unknown

   Alice                                                 Bob
   |                                                      |
   |                                                      |
   |   Alice offers BUNDLE support with unique address    |
   |        for the audio and video m-line                |
   |                                                      |
   |                                                      |
   |          Offer(Audio:Opus Video:VP8)                 |
   |----------------------------------------------------->|
   |                                                      |Bob
   |                                                      |supports
   |                                                      |BUNDLE
   |          Answer(Audio:Opus Video:VP8)                |
   |<-----------------------------------------------------|
   |                                                      |BUNDLE,
   |
   |                                                      |Bob uses                                                      |Uses
   |                                                      |identical
   |                                                      |addresses
   |                                                      |
   |  Updated Offer for Bundle Address Synchronization.   |
   |----------------------------------------------------->|
   |                                                      |
   |                                                      |                                                      |address
   |       Answer (Bob accepts the updated offer)          Answer(Audio:Opus Video:VP8)                |
   |<-----------------------------------------------------|
   |                                                      |
   |                                                      |
   |    2 Way Call with Audio and Video Multiplexed       |
   |......................................................|
   |                                                      |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice supports    |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54610 IN IP4 24.23.204.141 | [RFC3605] - RTCP port         |
   |                                   | different from RTP Port       |
   | a=mid:audio                       | [RFC5888] Audio m=line part of   |
   |                                   | of BUNDLE group with a unique |
   |                                   | port number                   |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264]                     |
   | a=rtcp:54609 IN IP4 a=rtpmap:109 opus/48000/2         | [RFC3605] [I-D.ietf-payload-rtp-opus]   |
   | 24.23.204.141 a=maxptime:120                    | [RFC4566]                     |
   | a=rtpmap:109 opus/48000/2 a=ice-ufrag:074c6550              | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=extmap:1 urn:ietf:params:rtp- a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC6464] [RFC5245]                     |
   | hdrext:ssrc-audio-level 74af08a068                        |                               |
   | a=ptime:20 a=fingerprint:sha-256 19:E2:1C:3B | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendrecv :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | [RFC3264]                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ssrc:11111                     | [RFC5576]                      |
   | cname:EocUG1f0fcg/yvY7 a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=rtcp-fb:109 nack                | [RFC5245] [RFC5104]                     |
   | 474af08a068 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | 9d:1f:66:79:a8:07 hdrext:sdes:mid                   | egotiation]                   |
   | a=candidate:0 1 UDP  2122194687 a=ssrc:12345                      | [RFC5245] [RFC5576]                     |
   | 192.168.1.4 54609 typ host cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP  2122194687   | [RFC5245] - RTP host          |
   | 192.168.1.4 54609 61665 typ host        | candidate                     |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245] - RTP Server        |
   | 24.23.204.141 54609 typ srflx     | Reflexive candidate           |
   | raddr 192.168.1.4 rport 54609 61665     |                               |
   | a=candidate:0 2 UDP 2122194687    | [RFC5245] - RTCP host         |
   | 192.168.1.4 61666 typ host        | candidate                     |
   | a=candidate:1 2 UDP  1685987071   | [RFC5245] - RTCP Server       |
   | 24.23.204.141 54609 54610 typ srflx     | Reflexive candidate           |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104]                      |
   | a=rtcp-rsize 61666     | [RFC5506]                               |
   | a=ice-options:trickle ****** Video m=line *********     | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=video 62537 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:62538 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:video                       | [RFC5888] Video m=line part of   |
   |                                   | of the Bundle group with a unique    |
   |                                   | unique port number            |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp-mux a=sendrecv                        | [RFC5761] [RFC3264]                     |
   | a=rtcp:62537 IN IP4 a=rtpmap:120 VP8/90000            | [RFC3605] - Port for RTCP data [I-D.ietf-payload-vp8]        |
   | 24.23.204.141 a=ice-ufrag:6550074c              | [RFC5245]                     |
   | a=rtpmap:120 VP8/90000 a=ice-pwd:74af08a068a28a397a4c3f3 | [I-D.ietf-payload-vp8] [RFC5245]                     |
   | a=sendrecv 1747d1ee34                        |                               |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | [RFC3264]                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=ssrc:22222                     | [RFC5576]                      |
   | cname:Q/NWs1ao1HmN4Xa5 a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:6550074c a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:74af08a068a28a397a4c3f a=rtcp-fb:120 nack                | [RFC5245] [RFC5104]                     |
   | 31747d1ee34 a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=fingerprint:sha-1 1f:ef:6d:f7: a=rtcp-fb:120 ccm fir             | [RFC5245] [RFC5104]                     |
   | c9:c7:70:9d:1f:66:99:41:49:83: a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | 4a:97:0e79:a8:07 hdrext:sdes:mid                   | egotiation]                   |
   | a=candidate:0 1 UDP  2122194687 a=ssrc:56789                      | [RFC5245] [RFC5576]                     |
   | 192.168.1.4 62537 typ host cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP  2122194687   | [RFC5245] - RTP Host          |
   | 192.168.1.4 62537 61886 typ host        | candidate                     |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245] - RTP Server        |
   | 24.23.204.141 62537 typ srflx     | Reflexive candidate           |
   | raddr 192.168.1.4 rport 62537 61886     |                               |
   | a=candidate:0 2 2122194687        | [RFC5245] - RTCP host         |
   | 192.168.1.4 61888 typ host        | candidate                     |
   | a=candidate:1 2 UDP 1685987071    | [RFC5245] - RTCP Server       |
   | 24.23.204.141 62537 62538 typ srflx     | Reflexive candidate           |
   | raddr 192.168.1.4 rport 62537    |                                |
   | a=rtcp-fb:120 nack               | [RFC5104]                      |
   | a=rtcp-fb:120 nack pli           | [RFC5104]                      | 61888     | a=rtcp-fb:120 ccm fir            | [RFC5104]                      |
   | a=rtcp-rsize                               | [RFC5506]                      |
   | a=ice-options:trickle            | [I-D.ietf-mmusic-trickle-ice]  |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                    Table 13: 5.2.7 SDP Offer w/BUNDLE

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Bob supports BUNDLE      |
   |                                   | BUNDLE semantics.             |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888] Audio m=line part   |
   |                                   | of the BUNDLE group           |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=mid:audio                      | [RFC5888] Audio m=line part of |
   | a=sendrecv                        | the BUNDLE group [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=ptime:20 a=maxptime:120                    | [I-D.ietf-payload-rtp-opus] [RFC4566]                     |
   | a=extmap:1 urn:ietf:params:rtp- a=ice-ufrag:c300d85b              | [RFC6464] [RFC5245]                     |
   | hdrext:ssrc-audio-level a=ice-pwd:de4e99bd291c325921d5d47 | [RFC5245]                     |
   | a=sendrecv efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145] - Bob carries out   |
   |                                   | DTLS Handshake in parallel    |
   | a=rtcp-fb:109 nack               | [RFC5104]                      |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ssrc:33333 a=rtcp-rsize                      | [RFC5576] [RFC5506]                     |
   | cname:Q/1HmN4Xa5NWs1ao a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:c300d85b a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 7efbabd9a2 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:54321                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2122194687    | [RFC5245]                     |
   | 192.168.1.7 49203 typ host        |                               |
   | a=candidate:1 1 UDP 1685987071    | [RFC5245]                     |
   | 98.248.92.77 49203 51556 typ srflx      |                               |
   | raddr 192.168.1.7 rport 49203     |                               |
   | a=rtcp-rsize                     | [RFC5506]                      |
   | a=ice-options:trickle ****** Video m=line *********     | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:video                       | [RFC5888] Video m=line part of   |
   |                                   | of the BUNDLE group with the port  |
   |                                   | port from audio line repeated |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtpmap:120 VP8/90000           | [I-D.ietf-payload-vp8]         |
   | a=sendrecv a=sendrecv                        | [RFC3264]                     |
   | a=setup:active                   | [RFC4145] - Bob carries out    |
   |                                  | DTLS Handshake in parallel     |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ssrc:44444                     | [RFC5576]                      |
   | cname:Q/2AqlmN4Xa5NWs            |                                |
   | a=ice-ufrag:85bc300d             | [RFC5245]                      |
   | a=ice-pwd:bd2de4e9991c325921d5d4 | [RFC5245]                      |
   | 7efbabd9a2                       |                                |
   | a=fingerprint:sha-1 41:49:83:4a: | [RFC5245]                      |
   | 99:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP 2122194687   | [RFC5245]                      |
   | 192.168.1.7 49203 typ host       |                                |
   | a=candidate:1 1 UDP 1685987071   | [RFC5245]                      |
   | 98.248.92.77 49203 typ srflx     |                                |
   | raddr 192.168.1.7 rport 49203    |                                |
   | a=rtcp-fb:120 nack               | [RFC5104]                      |
   | a=rtcp-fb:120 nack pli           | [RFC5104]                      |
   | a=rtcp-fb:120 ccm fir            | [RFC5104]                      |
   | a=rtcp-rsize                     | [RFC5506]                      |
   | a=ice-options:trickle            | [I-D.ietf-mmusic-trickle-ice]  |
   +----------------------------------+--------------------------------+

                    Table 14: 5.2.7 SDP Answer w/BUNDLE

   +----------------------------------+--------------------------------+
   | SDP Contents                     | RFC#/Notes                     |
   +----------------------------------+--------------------------------+
   | v=0                              | [RFC4566]                      |
   | o=- 20518 0 IN IP4 0.0.0.0       | [RFC4566]                      |
   | s=-                              | [RFC4566]                      |
   | t=0 0                            | [RFC4566]                      |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video       | [I-D.ietf-mmusic-sdp-bundle-ne |
   |                                  | gotiation]                     |
   | m=audio 54609 UDP/TLS/RTP/SAVPF  | [RFC4566]                      |
   | 109                              |                                |
   | c=IN IP4 24.23.204.141           | [RFC4566]                      |
   | a=msid:ma ta                     | Identifies RTCMediaStream ID   |
   |                                  | (ma) and RTCMediaStreamTrack   |
   |                                  | ID (ta)                        |
   | a=mid:audio                      | [RFC5888]  - Port number       |
   |                                  | finalized as Bundle Address.   |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=rtcp:54609 IN IP4              | [RFC3605]                      |
   | 24.23.204.141                    |                                |
   | a=rtpmap:109 opus/48000/2        | [I-D.ietf-payload-rtp-opus]    |
   | a=extmap:1 urn:ietf:params:rtp-  | [RFC6464]                      |
   | hdrext:ssrc-audio-level          |                                |
   | a=ptime:20                       | [I-D.ietf-payload-rtp-opus]    |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:actpass                  | [RFC4145]                      |
   | a=ssrc:11111                     | [RFC5576]                      |
   | cname:EocUG1f0fcg/yvY7           |                                |
   | a=ice-ufrag:074c6550             | [RFC5245]                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068                      |                                |
   | a=fingerprint:sha-1 99:41:49:83: | [RFC5245]                      |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP  2122194687  | [RFC5245]                      |
   | 192.168.1.4 54609 typ host       |                                |
   | a=candidate:1 1 UDP  1685987071  | [RFC5245]                      |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104]                      |
   | a=rtcp-rsize                     | [RFC5506]                      |
   | a=ice-options:trickle            | [I-D.ietf-mmusic-trickle-ice]  |
   | m=video 54609 UDP/TLS/RTP/SAVPF  | [RFC4566]                      |
   | 120                              |                                |
   | c=IN IP4 24.23.204.141           | [RFC4566]                      |
   | a=msid:ma tb                     | Identifies RTCMediaStream ID   |
   |                                  | (ma) and RTCMediaStreamTrack   |
   |                                  | ID (tb)                        |
   | a=mid:video                      | [RFC5888]                      |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:actpass                  | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ssrc:22222                     | [RFC5576]                      |
   | cname:Q/NWs1ao1HmN4Xa5           |                                |
   | a=ice-ufrag:074c6550 a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068                      |                                | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | a=fingerprint:sha-1 99:41:49:83: | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 9d:1f:66:79:a8:07 1:58:D0:A1:2C:19:08               |                               |
   | a=candidate:0 1 UDP  2122194687  | [RFC5245]                      |
   | 192.168.1.4 54609 typ host a=setup:active                    | [RFC4145] - Bob carries out   |
   | a=candidate:1 1 UDP  1685987071                                   | [RFC5245] DTLS Handshake in parallel    |
   | 24.23.204.141 54609 typ srflx a=rtcp-mux                        | [RFC5761]                     |
   | raddr 192.168.1.4 rport 54609 a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=rtcp-rsize a=extmap:2 urn:ietf:params:rtp-   | [RFC5506] [I-D.ietf-mmusic-sdp-bundle-n |
   | a=ice-options:trickle hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:98765                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5            | [I-D.ietf-mmusic-trickle-ice]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                    Table 15: 14: 5.2.7 SDP Offer for BAS Answer w/BUNDLE

5.2.8.  Audio, Video and Data Session

   This example shows SDP for negotiating a session with Audio, Video
   and data streams between Alice and Bob with BUNDLE support known.

       Audio,Video,Data with BUNDLE support known

   Alice                                       Bob
   |                                            |
   |                                            |
   |Alice
   |   Alice indicates BUNDLE support with      |
   |identical
   |  identical address across all the m=lines  |
   |                                            |
   |                                            |
   |     Offer(Audio:Opus Video:VP8 Data)       |
   |------------------------------------------->|
   |                                            |Bob does
   |                                            |the same
   |    Answer(Audio:Opus,Video:VP8 Data)       |
   |<-------------------------------------------|
   |                                            |
   |                                            |
   |                                            |
   |    Two-way Audio,Video, Data multiplexed   |
   |............................................|
   |                                            |
   |                                            |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video data   | [I-D.ietf-mmusic-sdp-bundle-ne |
   |                                  | gotiation]                     |
   | m=audio 54609 UDP/TLS/RTP/SAVPF  | [RFC4566]                      |
   | 109                              |                                |
   | c=IN IP4 24.23.204.141           | [RFC4566]                      |
   | a=msid:ma ta                     | Identifies RTCMediaStream ID   |
   |                                  | (ma) and RTCMediaStreamTrack   |
   |                                  | ID (ta)                        |
   | a=rtcp:54609 IN IP4              | [RFC3605]                      |
   | 24.23.204.141                    |                                |
   | a=mid:audio                      | [RFC5888]                      |
   | a=rtpmap:109 opus/48000/2        | [I-D.ietf-payload-rtp-opus]    |
   | a=extmap:1 urn:ietf:params:rtp-  | [RFC6464]                      |
   | hdrext:ssrc-audio-level          |                                |
   | a=ptime:20                       | [I-D.ietf-payload-rtp-opus]    |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:actpass                  | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ice-ufrag:074c6550             | [RFC5245]                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068                      |                                |
   | a=fingerprint:sha-1 99:41:49:83: | [RFC5245]                      |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP  2122194687  | [RFC5245]                      |
   | 192.168.1.4 54609 typ host       |                                |
   | a=candidate:0 2 UDP 2122194687   | [RFC5245]                      |
   | 192.168.1.4 64678 typ host       |                                |
   | a=candidate:1 1 UDP  1685987071  | [RFC5245]                      |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=candidate:1 2 UDP  1685987071  | [RFC5245]                      |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104]                      |
   | a=ssrc:11111                     | [RFC5576] [I-D.ietf-mmusic-sdp-bundle-n |
   | cname:Q/NWs1ao1HmN4Xa5                                   | egotiation]                   |
   | a=rtcp-rsize a=ice-options:trickle             | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | a=ice-options:trickle ****** Audio m=line *********     | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=video m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=msid:ma tb ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb) (ta)                       |
   | a=rtcp:54609 IN IP4 a=mid:audio                       | [RFC3605] [RFC5888]                     |
   | 24.23.204.141 a=sendrecv                        | [RFC3264]                     |
   | a=mid:video a=rtpmap:109 opus/48000/2         | [RFC5888] [I-D.ietf-payload-rtp-opus]   |
   | a=rtpmap:120 VP8/90000 a=maxptime:120                    | [I-D.ietf-payload-vp8] [RFC4566]                     |
   | a=sendrecv a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245]                     |
   | 74af08a068                        |                               |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | [RFC3264]                               |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=rtcp-fb:109 nack                | [RFC5245] [RFC5104]                     |
   | 474af08a068 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | 9d:1f:66:79:a8:07 hdrext:sdes:mid                   | egotiation]                   |
   | a=candidate:0 1 UDP  2122194687 a=ssrc:12345                      | [RFC5245] [RFC5576]                     |
   | 192.168.1.4 54609 typ host cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP  2122194687   | [RFC5245]                     |
   | 192.168.1.4 54609 61665 typ host        |                               |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 61665     |                               |
   | a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Video m=line *********     | ***************************** |
   | m=video 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | a=candidate:1 2 UDP  1685987071 120                               | [RFC5245]                               |
   | c=IN IP4 24.23.204.141 54609 typ srflx            | [RFC4566]                     |
   | raddr 192.168.1.4 rport 54609 a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=sendrecv                        | [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               |                               |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=ssrc:22222 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:56789                      | [RFC5576]                     |
   | cname:Q/aoNWs11HmN4Xa5 cname:EocUG1f0fcg/yvY7            |                               |
   | a=rtcp-rsize ****** Application m=line         | [RFC5506] ***************************** |
   | a=ice-options:trickle *********                         | [I-D.ietf-mmusic-trickle-ice]                               |
   | m=application 54609 DTLS/SCTP UDP/DTLS/SCTP | [I-D.ietf-rtcweb-data-channel] [I-D.ietf-rtcweb-data-channel |
   | 5000 webrtc-datachannel                | ]                             |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=mid:data                        | [RFC5888]                     |
   | a=sctpmap:5000 webrtc- a=sctp-port:5000                  | [I-D.ietf-mmusic-sctp-sdp]    |
   | DataChannel                      |                                |
   | streams=1;label="channel 1";     |                                |
   | subprotocol="chat"; a=max-message-size:100000         | [I-D.ietf-mmusic-sctp-sdp]    |
   | a=sendrecv                        | [RFC3264]                     |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=ice-ufrag:074c6550             | [RFC5245]                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068 a=connection:new                  | [RFC4145]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=ice-ufrag:074c6550              | [RFC5245]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP  2122194687 a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245]                     |
   | 192.168.1.4 54609 typ host 74af08a068                        |                               |
   | a=candidate:1 1 UDP  1685987071 a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | raddr 192.168.1.4 rport 54609 :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | a=ice-options:trickle 9:26:33:E8:70:88:A2               | [I-D.ietf-mmusic-trickle-ice]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 16: 15: 5.2.8 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 16833 0 IN IP4 0.0.0.0        | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video data   | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | Bob's trickle support support  |
   |                                  | is indicated at the session    |
   |                                  | level ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=mid:audio                       | [RFC5888]                     |
   | a=sendrecv                        | [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:c300d85b              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:de4e99bd291c325921d5d47 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendrecv efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:c300d85b a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 7efbabd9a2 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:54321                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2122194687    | [RFC5245]                     |
   | 192.168.1.7 49203 51556 typ host        |                               |
   | a=candidate:1 1 UDP 1685987071    | [RFC5245]                     |
   | 98.248.92.77 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 49203    |                                | 51556     | a=ssrc:33333                     | [RFC5576]                               |
   | cname:L/aoNWs11HmN4Xa5 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=mid:video a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:active                   | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ice-ufrag:c300d85b             | [RFC5245]                      |
   | a=ice-pwd:de4e99bd291c325921d5d4 | [RFC5245]                      |
   | 7efbabd9a2                       |                                |
   | a=fingerprint:sha-1 99:41:49:83: a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP 2122194687 :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [RFC5245]                               |
   | 192.168.1.7 49203 typ host 1:58:D0:A1:2C:19:08               |                               |
   | a=candidate:1 1 UDP 1685987071 a=setup:active                    | [RFC5245] [RFC4145]                     |
   | 98.248.92.77 49203 typ srflx a=rtcp-mux                        | [RFC5761]                     |
   | raddr 192.168.1.7 rport 49203 a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=ssrc:44444 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:98765                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=rtcp-rsize ****** Application m=line         | ***************************** |
   | *********                         | [RFC5506]                               |
   | m=application 49203 DTLS/SCTP UDP/DTLS/SCTP | [I-D.ietf-mmusic-sctp-sdp]    |
   | 5000 webrtc-datachannel                |                               |
   | c=IN IP4 98.248.92.771            | [RFC4566]                     |
   | a=mid:data                        | [RFC5888]                     |
   | a=sctpmap:5000 webrtc- a=sctp-port:5000                  | [I-D.ietf-mmusic-sctp-sdp]    |
   | DataChannel                      |                                |
   | streams=16;label="channel 1";    |                                |
   | subprotocol="chat"; a=max-message-size:100000         | [I-D.ietf-mmusic-sctp-sdp]    |
   | a=setup:active                    | [RFC4145]                     |
   | a=sendrecv                        | [RFC3264]                     |
   | a=ice-ufrag:c300d85b             | [RFC5245]                      |
   | a=ice-pwd:de4e99bd291c325921d5d4 a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | 7efbabd9a2 :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | a=fingerprint:sha-1 99:41:49:83: :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [RFC5245]                      |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP 2122194687   | [RFC5245]                      |
   | 192.168.1.7 49203 typ host       |                                |
   | a=candidate:1 1 UDP 1685987071   | [RFC5245]                      |
   | 98.248.92.77 49203 typ srflx                               |
   |
   | raddr 192.168.1.7 rport 49203 1:58:D0:A1:2C:19:08               |                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                        Table 17: 16: 5.2.8 SDP Answer

5.2.9.  Audio, Video Session with BUNDLE Unsupported

   This use-case illustrates SDP Offer/Answer exchange where the far-end
   (Bob) either doesn't support media bundling or doesn't want to group
   m=lines over a single 5-tuple.

   The same is indicated by dropping the "a=group:BUNDLE" line and
   BUNDLE RTP header extension in the Answer SDP.

   On successful Offer/Answer exchange, Alice and Bob each end up using
   unique 5-tuple for audio and video media streams respectively.

      Two-Way Secure Audio,Video with BUNDLE Unsupported

   Alice                                                 Bob
   |                                                      |
   |                                                      |
   |     Alice offers BUNDLE support with unique address  |
   |           for the audio and video m-line             |
   |                                                      |
   |                                                      |
   |           Offer(Audio:Opus Video:VP8)                |
   |----------------------------------------------------->|
   |                                                      |Bob
   |                                                      |doesn't
   |                                                      |support
   |                                                      |BUNDLE
   |           Answer(Audio:Opus Video:VP8)               |
   |<-----------------------------------------------------|
   |                                                      |Bob uses
   |                                                      |unique
   |                                                      |addresses
   |                                                      |across the
   |                                                      |m=lines
   |                                                      |
   |2Way Call with Audio and Video on different 5-tuples  |
   |......................................................|
   |                                                      |
   |                                                      |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                      |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid] [RFC4566]                     |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice supports    |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 55232 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=msid:ma ta                     | Identifies RTCMediaStream ID   |
   | a=rtcp:55232 IN IP4 24.23.204.141 | (ma) and RTCMediaStreamTrack [RFC3605] - RTCP port         |
   |                                   | ID (ta) different from RTP port       |
   | a=mid:audio                       | [RFC5888] Audio m=line part of   |
   |                                   | of BUNDLE group with a unique |
   |                                   | port number                   |
   | a=rtcp:55232 IN IP4 a=msid:ma ta                      | [RFC3605] Identifies RTCMediaStream ID  |
   | 24.23.204.141                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=sendrecv                        | [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245]                     |
   | 74af08a068                        |                               |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | [I-D.ietf-payload-rtp-opus]                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=sendrecv a=rtcp-mux                        | [RFC3264] [RFC5761]                     |
   | a=rtcp-mux a=rtcp-rsize                      | [RFC5761] [RFC5506]                     |
   | a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ssrc:11111                     | [RFC5576]                      |
   | cname:EocUG1f0fcg/yvY7           |                                |
   | a=ice-ufrag:074c6550 a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 474af08a068 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d a=ssrc:12345                      | [RFC5576]                     |
   | : 1f:66:79:a8:07 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 1 UDP  2122194687   | [RFC5245]                     |
   | 192.168.1.4 55232 typ host       |                                |
   | a=candidate:0 2 UDP 2122194687   | [RFC5245]                      |
   | 192.168.1.4 55232 61665 typ host        |                               |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245]                     |
   | 24.23.204.141 55232 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 55232 61665     |                               |
   | a=candidate:0 2 UDP 2122194687    | [RFC5245]                     |
   | 192.168.1.4 61666 typ host        |                               |
   | a=candidate:1 2 UDP  1685987071   | [RFC5245]                     |
   | 24.23.204.141 55232 typ srflx     |                               |
   | raddr 192.168.1.4 rport 55232 61666     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | ****** Video m=line *********     | ***************************** |
   | m=video 54332 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:60052 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:video                       | [RFC5888] Video m=line part   |
   |                                   | of the BUNDLE group with a    |
   |                                   | unique port number            |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=mid:video a=sendrecv                        | [RFC5888] Video m=line part of [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | the BUNDLE group with a unique [I-D.ietf-payload-vp8]        |
   | a=ice-ufrag:7872093               | port number [RFC5245]                     |
   | a=rtcp:54332 IN IP4 a=ice-pwd:ee3474af08a068a28a397a4 | [RFC3605] [RFC5245]                     |
   | 24.23.204.141 c3f31747d1                        |                               |
   | a=rtpmap:120 VP8/90000 a=fingerprint:sha-256 19:E2:1C:3B | [I-D.ietf-payload-vp8] [RFC5245]                     |
   | a=sendrecv :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | [RFC3264]                               |
   | a=setup:actpass                   | [RFC4145] - Alice can perform |
   |                                   | DTLS before Answer arrives    |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ssrc:22222                     | [RFC5576]                      |
   | cname:yvY7/EocUG1f0fcg           |                                |
   | a=ice-ufrag:7872093              | [RFC5245]                      |
   | a=ice-pwd:ee3474af08a068a28a397a a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | 4c3f31747d1 a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=fingerprint:sha-1 6d:f7:c9:c7: a=rtcp-fb:120 nack pli            | [RFC5245] [RFC5104]                     |
   | 70:9d:1f:66:79:a8:07:99:41: a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | 49:83:4a:97:0e:1f:ef a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=candidate:0 1 UDP  2122194687 hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 192.168.1.4 54332 typ host a=ssrc:56789                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP  2122194687   | [RFC5245]                     |
   | 192.168.1.4 54332 71775 typ host        |                               |
   | a=candidate:1 1 UDP  1685987071   | [RFC5245]                     |
   | 24.23.204.141 54332 typ srflx     |                               |
   | raddr 192.168.1.4 rport 54332 71775     |                               |
   | a=candidate:0 2 2122194687        | [RFC5245]                     |
   | 192.168.1.4 71776 typ host        |                               |
   | a=candidate:1 2 UDP 1685987071    | [RFC5245]                     |
   | 24.23.204.141 54332 60052 typ srflx     |                               |
   | raddr 192.168.1.4 rport 54332    | 71776     |                               | a=rtcp-fb:120 nack               | [RFC5104]                      |
   | a=rtcp-fb:120 nack pli           | [RFC5104]                      |
   | a=rtcp-fb:120 ccm fir            | [RFC5104]                      |
   | a=rtcp-rsize                     | [RFC5506]                      |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                    Table 18: 17: 5.2.9 SDP Offer w/BUNDLE

   +---------------------------------------+---------------------------+

   +----------------------------------------+--------------------------+
   | Answer SDP Contents                    | RFC#/Notes               |
   +---------------------------------------+---------------------------+
   +----------------------------------------+--------------------------+
   | v=0                                    | [RFC4566]                |
   | o=-  16833 0 IN IP4 0.0.0.0            | [RFC4566]                |
   | s=-                                    | [RFC4566]                |
   | t=0 0                                  | [RFC4566]                |
   | a=msid-semantic:WMS ma a=ice-options:trickle                  | [I-D.ietf-mmusic-trickle | [I-D.ietf-mmusic-msid]
   |                                        | a=ice-options:trickle -ice]                    |
   | [I-D.ietf-mmusic-trickle- ****** Audio m=line *********          | ************************ |
   | ice]                                        | *****                    |
   | m=audio 53214 UDP/TLS/RTP/SAVPF 109    | [RFC4566]                |
   | c=IN IP4 98.248.92.77                  | [RFC4566]                |
   | a=rtcp:60065 IN IP4 98.248.92.77       | [RFC3605]                |
   | a=msid:ma ta                           | Identifies RTCMediaStream               |
   |                                        | RTCMediaStream ID (ma) and   |
   |                                        | and RTCMediaStreamTrack ID  |
   |                                        | ID (ta)                  |
   | a=rtcp:60065 IN IP4 98.248.92.77 a=sendrecv                             | [RFC3605] [RFC3264]                |
   | a=rtpmap:109 opus/48000/2              | [I-D.ietf-payload-rtp-opu [I-D.ietf-payload-rtp-op |
   |                                        | s] us]                      |
   | a=extmap:1 urn:ietf:params:rtp-hdrext a=maxptime:120                         | [RFC6464] [RFC4566]                |
   | :ssrc-audio-level a=ice-ufrag:c300d85b                   | [RFC5245]                |
   | a=ptime:20 a=ice-                                 | [RFC5245]                |
   | pwd:de4e99bd291c325921d5d47efbabd9a2   |                          |
   | a=fingerprint:sha-256 6B:8B:F0:65:5F:7 | [RFC5245]                |
   | 8:E2:51:3B:AC:6F:F3:3F:46:1B:35 :DC:B8 |                          |
   | :5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:1 | [I-D.ietf-payload-rtp-opu                          |
   | 9:08                                   | s]                          |
   | a=setup:active                         | [RFC4145] - Bob carries  |
   |                                        | out DTLS Handshake in    |
   |                                        | parallel                 |
   | a=sendrecv a=rtcp-rsize                           | [RFC3264] [RFC5506]                |
   | a=rtcp-fb:109 nack                     | [RFC5104]                |
   | a=ice-ufrag:c300d85b                  | [RFC5245]                 |
   | a=ice-                                | [RFC5245]                 |
   | pwd:de4e99bd291c325921d5d47efbabd9a2  |                           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97 a=extmap:1 urn:ietf:params:rtp-hdrext  | [RFC5245] [RFC6464]                |
   | :0e:1f:ef:6d:f7:c9:c7:70: :ssrc-audio-level                      |                          |
   | 9d:1f:66:79:a8:07 a=ssrc:54321 cname:Q/NWs1ao1HmN4Xa5    | [RFC5576]                |
   | a=candidate:0 1 UDP 2122194687         | [RFC5245]                |
   | 192.168.1.7 53214 51556 typ host             |                          |
   | a=candidate:1 1 UDP 1685987071         | [RFC5245]                |
   | 98.248.92.77 53214 typ srflx raddr     |                          |
   | 192.168.1.7 rport 53214 51556                |                          |
   | a=candidate:0 2 UDP 2122194687         | [RFC5245]                |
   | 192.168.1.7 60065 51558 typ host             |                          |
   | a=candidate:1 2 UDP 1685987071         | [RFC5245]                |
   | 98.248.92.77 60065 typ srflx raddr     |                          |
   | 192.168.1.7 rport 60065 51558                |                          |
   | a=rtcp-rsize ****** Video m=line *********          | ************************ |
   | [RFC5506]                                        | *****                    |
   | m=video 58679 UDP/TLS/RTP/SAVPF 120    | [RFC4566]                |
   | c=IN IP4 98.248.92.77                  | [RFC4566]                |
   | a=rtcp:56507 IN IP4 98.248.92.77       | [RFC3605]                |
   | a=msid:ma tb                           | Identifies RTCMediaStream               |
   |                                        | RTCMediaStream ID (ma) and   |
   |                                        | and RTCMediaStreamTrack ID  |
   |                                        | ID (tb)                  |
   | a=rtcp:56507 IN IP4 98.248.92.77 a=sendrecv                             | [RFC3605] [RFC3264]                |
   | a=rtpmap:120 VP8/90000                 | [I-D.ietf-payload-vp8]   |
   | a=ice-ufrag:85bC300                    | [RFC5245]                |
   | a=ice-                                 | [RFC5245]                |
   | pwd:325921d5d47efbabd9a2de4e99bd291c   |                          |
   | a=fingerprint:sha-256 6B:8B:F0:65:5F:7 | [RFC5245]                |
   | 8:E2:51:3B:AC:6F:F3:3F:46:1B:35 :DC:B8 |                          |
   | :5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:1 |                          |
   | 9:08                                   |                          |
   | a=setup:active                         | [RFC4145] - Bob carries  |
   |                                        | out DTLS Handshake in    |
   |                                        | parallel                 |
   | a=sendrecv                            | [RFC3264]                 |
   | a=ice-ufrag:85bC300                   | [RFC5245]                 |
   | a=ice- a=rtcp-rsize                           | [RFC5245] [RFC5506]                |
   | pwd:325921d5d47efbabd9a2de4e99bd291c a=rtcp-fb:120 nack                     | [RFC5104]                |
   | a=fingerprint:sha-1 9d:1f:66:79:a8:07 a=rtcp-fb:120 nack pli                 | [RFC5245] [RFC5104]                |
   | :99:41:49:83:4a:97:0e:1f: a=rtcp-fb:120 ccm fir                  | [RFC5104]                |
   | ef:6d:f7:c9:c7:70 a=ssrc:98765 cname:Q/NWs1ao1HmN4Xa5    | [RFC5576]                |
   | a=candidate:0 1 UDP 2122194687         | [RFC5245]                |
   | 192.168.1.7 58679 61556 typ host             |                          |
   | a=candidate:1 1 UDP 1685987071         | [RFC5245]                |
   | 98.248.92.77 58679 typ srflx raddr     |                          |
   | 192.168.1.7 rport 58679 61556                |                          |
   | a=candidate:0 1 UDP 2122194687         | [RFC5245]                |
   | 192.168.1.7 56507 61558 typ host             |                          |
   | a=candidate:1 1 UDP 1685987071         | [RFC5245]                 |
   | 98.248.92.77 56507 typ srflx raddr    |                           |
   | 192.168.1.7 rport 58679               |                           |
   | a=rtcp-fb:120 nack                    | [RFC5104]                 |
   | a=rtcp-fb:120 nack pli                | [RFC5104] [RFC5245]                |
   | a=rtcp-fb:120 ccm fir 98.248.92.77 56507 typ srflx raddr     | [RFC5104]                          |
   | a=rtcp-rsize 192.168.1.7 rport 61558                | [RFC5506]                          |
   +---------------------------------------+---------------------------+
   +----------------------------------------+--------------------------+

                 Table 19: 18: 5.2.9 SDP Answer without BUNDLE

5.2.10.  Audio, Video BUNDLED, but Data (Not BUNDLED)

   This example show-cases SDP for negotiating a session with Audio,
   Video and data streams between Alice and Bob with data stream not
   being part of the BUNDLE group.  This is shown by assigning unique
   port for data media sections. section and not adding the "mid" identification
   tag to the BUNDLE group.

          Audio, Video, with Data (Not in BUNDLE)

   Alice                                                 Bob
   |                                                      |
   |                                                      |
   |Alice wants to multiplex audio, video but not data    |
   |                                                      |
   |                                                      |
   |  Offer(Audio:Opus Video:VP8, Data(not in BUNDLE))    |
   |----------------------------------------------------->|
   |                                                      |
   |                                                      |
   |       Answer(Audio:Opus Video:VP8, Data)             |
   |<-----------------------------------------------------|
   |                                                      |
   |                                                      |
   |2 Way Call with Audio, Video Multiplexed except data  |
   |......................................................|
   |                                                      |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice wants to    |
   |                                   | BUNDLE only audio and video   |
   |                                   | media.                        |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:54609 IN IP4 a=sendrecv                        | [RFC3605] [RFC3264]                     |
   | 24.23.204.141 a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=mid:audio a=maxptime:120                    | [RFC5888] [RFC4566]                     |
   | a=rtpmap:109 opus/48000/2 a=ice-ufrag:074c6550              | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=extmap:1 urn:ietf:params:rtp- a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC6464] [RFC5245]                     |
   | hdrext:ssrc-audio-level 74af08a068                        |                               |
   | a=ptime:20 a=fingerprint:sha-256 19:E2:1C:3B | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendrecv :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | [RFC3264]                               |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=rtcp-fb:109 nack                | [RFC5245] [RFC5104]                     |
   | 474af08a068 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | 9d:1f:66:79:a8:07 hdrext:sdes:mid                   | egotiation]                   |
   | a=candidate:0 1 UDP  2113667327 a=ssrc:12345                      | [RFC5245] [RFC5576]                     |
   | 192.168.1.4 54609 typ host cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326  2113667327   | [RFC5245]                     |
   | 192.168.1.4 54609 typ host        |                               |
   | a=rtcp-fb:109 nack               | [RFC5104]                      |
   | a=ssrc:11111                     | [RFC5576]                      |
   | cname:Q/NWs1ao1HmN4Xa5 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp:54609 IN IP4              | [RFC3605]                      |
   | 24.23.204.141                    |                                |
   | a=mid:video a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:actpass                  | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ice-ufrag:074c6550             | [RFC5245]                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068                      |                                |
   | a=fingerprint:sha-1 99:41:49:83: a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | 9d:1f:66:79:a8:07 :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | a=candidate:0 1 UDP  2113667327 9:26:33:E8:70:88:A2               | [RFC5245]                               |
   | 192.168.1.4 54609 typ host a=setup:actpass                   | [RFC4145]                     |
   | a=candidate:0 2 UDP 2113667326 a=rtcp-mux                        | [RFC5245] [RFC5761]                     |
   | 192.168.1.4 54609 typ host a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=ssrc:22222 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:56789                      | [RFC5576]                     |
   | cname:Q/aoNWs11HmN4Xa5 cname:EocUG1f0fcg/yvY7            |                               |
   | a=rtcp-rsize ****** Application m=line         | ***************************** |
   | *********                         | [RFC5506]                               |
   | m=application 10000 DTLS/SCTP UDP/DTLS/SCTP | [I-D.ietf-rtcweb-data-channel] [I-D.ietf-rtcweb-data-channel |
   | 5000 webrtc-datachannel                | ]                             |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=mid:data                        | [RFC5888]                     |
   | a=sctpmap:5000 webrtc- a=sctp-port:5000                  | [I-D.ietf-mmusic-sctp-sdp]    |
   | DataChannel                      |                                |
   | streams=16;label="channel 1";    |                                |
   | subprotocol="chat"; a=max-message-size:100000         | [I-D.ietf-mmusic-sctp-sdp]    |
   | a=sendrecv                        | [RFC3264]                     |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=connection:new                  | [RFC4145]                     |
   | a=ice-ufrag:89819013              | [RFC5245]                     |
   | a=ice-pwd:1747d1ee3474af08a068a2 a=ice-pwd:1747d1ee3474af08a068a28 | [RFC5245]                     |
   | 8a397a4c3f3 a397a4c3f3                        |                               |
   | a=fingerprint:sha-1 0e:1f:ef:6d: a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | f7:c9:c7:70:99:41:49:83:4a:97: :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               | 9d:1f:66:79:a8:07
   | 9:26:33:E8:70:88:A2               |                               |
   | a=candidate:0 1 UDP  2113667327   | [RFC5245]                     |
   | 192.168.1.4 10000 typ host        |                               |
   +----------------------------------+--------------------------------+
   | a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +-----------------------------------+-------------------------------+

                        Table 20: 19: 5.2.10 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=mid:audio a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:c300d85b              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:de4e99bd291c325921d5d47 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendrecv efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:c300d85b a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 7efbabd9a2 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7: a=ssrc:54321                      | [RFC5576]                     |
   | 70:9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 49203 typ host        |                               |
   | a=ssrc:33333                     | [RFC5576]                      |
   | cname:L/aoNWs11HmN4Xa5 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 98.248.92.771            | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=mid:video a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:active                   | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ice-ufrag:c300d85b             | [RFC5245]                      |
   | a=ice-pwd:de4e99bd291c325921d5d4 a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | 7efbabd9a2 :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | a=fingerprint:sha-1 99:41:49:83: :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: 1:58:D0:A1:2C:19:08               |                               |
   | 9d:1f:66:79:a8:07 a=setup:active                    | [RFC4145]                     |
   | a=candidate:0 1 UDP 2113667327 a=rtcp-mux                        | [RFC5245] [RFC5761]                     |
   | 192.168.1.7 49203 typ host a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=ssrc:44444 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:98765                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=rtcp-rsize ****** Application m=line         | ***************************** |
   | *********                         | [RFC5506]                               |
   | m=application 20000 DTLS/SCTP UDP/DTLS/SCTP | [I-D.ietf-mmusic-sctp-sdp]    |
   | 5000 webrtc-datachannel                |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=mid:data                        | [RFC5888]                     |
   | a=sctpmap:5000 webrtc- a=sctp-port:5000                  | [I-D.ietf-mmusic-sctp-sdp]    |
   | DataChannel                      |                                |
   | streams=1;label="channel 1";     |                                |
   | subprotocol="chat"; a=max-message-size:100000         | [I-D.ietf-mmusic-sctp-sdp]    |
   | a=setup:active                    | [RFC4145]                     |
   | a=sendrecv                        | [RFC3264]                     |
   | a=ice-ufrag:991Ca2a5e             | [RFC5245]                     |
   | a=ice-pwd:921d5d47efbabd9a2de4e9 a=ice-pwd:921d5d47efbabd9a2de4e99 | [RFC5245]                     |
   | 9bd291c325 bd291c325                         |                               |
   | a=fingerprint:sha-1 6d:f7:c9:c7: a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | 70:9d:1f:66:79:a8:07:99:41:49: :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 83:4a:97:0e:1f:ef 1:58:D0:A1:2C:19:08               |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 20000 typ host        |                               |
   +----------------------------------+--------------------------------+
   | a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   +-----------------------------------+-------------------------------+

                        Table 21: 20: 5.2.10 SDP Answer

5.2.11.  Audio Only, Add Video to BUNDLE

   This example involves 2 Offer/Answer exchanges.  First one setting up is used to
   negotiate and setup BUNDLE support for Audio-only session followed by
   an updated Offer/Answer exchange to add video stream to the ongoing
   session.  Also the newly added video stream is BUNDLED with the audio
   stream.

            Audio Only , Add Video and BUNDLE

   Alice                                                 Bob
   |                                                      |
   |                                                      |
   |        Alice indicates support for BUNDLE            |
   |                                                      |
   |                Offer(Audio:Opus)                     |
   |----------------------------------------------------->|
   |                                                      |Bob
   |                                                      |supports
   |                                                      |BUNDLE
   |                Answer(Audio:Opus)                    |
   |<-----------------------------------------------------|
   |                                                      |Alice adds
   |                                                      |video stream
   |        Updated Offer(Audio:Opus, Video:VP8)          |to BUNDLE
   |----------------------------------------------------->|
   |                                                      |
   |                                                      |Bob accepts
   |        Updated Answer(Audio:Opus, Video:VP8)         |
   |<-----------------------------------------------------|
   |                                                      |
   |   2Way Call with Audio and Video Multiplexed         |
   |......................................................|
   |                                                      |
   |                                                      |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice wants to adds audio  |
   |                                   | m=line to the BUNDLE only audio and video group    |
   | a=ice-options:trickle             | media. [I-D.ietf-mmusic-trickle-ice] |
   | a=ice-options:trickle ****** Audio m=line *********     | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:64678 IN IP4              | [RFC3605]                      |
   | 24.23.204.141                    |                                |
   | a=mid:audio a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee34 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendrecv 74af08a068                        | [RFC3264]                               |
   | a=setup:actpass a=fingerprint:sha-256 19:E2:1C:3B | [RFC4145] [RFC5245]                     |
   | a=rtcp-mux :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | [RFC5761]                               |
   | a=ice-ufrag:074c6550 :04 :BB:05:2F:70:9F:04:A9:0E:05:E | [RFC5245]                               |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 9:26:33:E8:70:88:A2               | [RFC5245]                               |
   | 474af08a068 a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     | a=fingerprint:sha-1 99:41:49:83:
   | [RFC5245] a=rtcp-rsize                      | [RFC5506]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=rtcp-fb:109 nack                | [RFC5104]                     |
   | 9d:1f:66:79:a8:07 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=candidate:0 1 UDP  2113667327 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 192.168.1.4 54609 typ host a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=candidate:1 1 UDP  694302207 hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 24.23.204.141 54609 typ srflx a=ssrc:12345                      | [RFC5576]                     |
   | raddr 192.168.1.4 rport 54609 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326  2113667327   | [RFC5245]                     |
   | 192.168.1.4 64678 61665 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206  694302207    | [RFC5245]                     |
   | 24.23.204.141 64678 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 64678    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104]                      |
   | a=ssrc:11111                     | [RFC5576] 61665     |                               | cname:Q/NWs1ao1HmN4Xa5           |
   | a=end-of-candidates               | a=rtcp-rsize                     | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                        Table 22: 21: 5.2.11 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=extmap:1 urn:ietf:params:rtp- a=rtcp:49203 IN IP4 98.248.92.77  | [RFC6464] [RFC3605]                     |
   | hdrext:ssrc-audio-level a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:audio a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=ptime:20 a=maxptime:120                    | [I-D.ietf-payload-rtp-opus] [RFC4566]                     |
   | a=sendrecv a=ice-ufrag:c300d85b              | [RFC5245]                     |
   | a=ice-pwd:de4e99bd291c325921d5d47 | [RFC5245]                     |
   | efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:c300d85b a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 7efbabd9a2 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7: a=ssrc:54321                      | [RFC5576]                     |
   | 70:9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 49203 51556 typ host        |                               |
   | a=candidate:1 1 UDP 1694302207    | [RFC5245]                     |
   | 98.248.92.77 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 49203    |                                |
   | a=ssrc:33333                     | [RFC5576]                      | 51556     | cname:L/aoNWs11HmN4Xa5                               |
   | a=end-of-candidates               | a=rtcp-rsize                     | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                        Table 23: 22: 5.2.10 SDP Answer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Updated Offer SDP Contents        | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=1                               | Version number incremented    |
   |                                   | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne |
   |                                  | gotiation] Alice wants to [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | BUNDLE only audio and video egotiation]                   |
   | a=ice-options:trickle             | media. [I-D.ietf-mmusic-trickle-ice] |
   | a=ice-options:trickle ****** Audio m=line *********     | [I-D.ietf-mmusic-trickle-ice] ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=extmap:1 urn:ietf:params:rtp- a=rtcp:54609 IN IP4 24.23.204.141 | [RFC6464] [RFC3605]                     |
   | hdrext:ssrc-audio-level a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:64678 IN IP4 a=sendrecv                        | [RFC3605] [RFC3264]                     |
   | 24.23.204.141 a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=mid:audio a=maxptime:120                    | [RFC5888] [RFC4566]                     |
   | a=rtpmap:109 opus/48000/2 a=ice-ufrag:074c6550              | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee34 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendrecv 74af08a068                        | [RFC3264]                               |
   | a=setup:actpass a=fingerprint:sha-256 19:E2:1C:3B | [RFC4145] [RFC5245]                     |
   | a=rtcp-mux :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | [RFC5761]                               |
   | a=ice-ufrag:074c6550 :04 :BB:05:2F:70:9F:04:A9:0E:05:E | [RFC5245]                               |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 9:26:33:E8:70:88:A2               | [RFC5245]                               |
   | 474af08a068 a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | a=fingerprint:sha-1 99:41:49:83: [RFC5761]                     | [RFC5245]
   | a=rtcp-rsize                      | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d [RFC5506]                     |
   | a=rtcp-fb:109 nack                | : 1f:66:79:a8:07 [RFC5104]                     |
   | a=extmap:1 urn:ietf:params:rtp-   | a=candidate:0 1 UDP  2113667327 [RFC6464]                     | [RFC5245]
   | hdrext:ssrc-audio-level           | 192.168.1.4 54609 typ host                               |
   | a=extmap:2 urn:ietf:params:rtp-   | a=candidate:1 1 UDP  694302207 [I-D.ietf-mmusic-sdp-bundle-n | [RFC5245]
   | hdrext:sdes:mid                   | 24.23.204.141 54609 typ srflx egotiation]                   |
   | a=ssrc:12345                      | [RFC5576]                     |
   | raddr 192.168.1.4 rport 54609 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326  2113667327   | [RFC5245]                     |
   | 192.168.1.4 64678 61665 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206  694302207    | [RFC5245]                     |
   | 24.23.204.141 64678 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 64678    |                                |
   | a=rtcp-fb:109 nack               | [RFC5104] 61665     |                               | a=ssrc:11111                     | [RFC5576]                      |
   | cname:Q/NWs1ao1HmN4Xa5 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp:64678 IN IP4              | [RFC3605]                      |
   | 24.23.204.141                    |                                |
   | a=mid:video a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:actpass                  | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ice-ufrag:074c6550             | [RFC5245]                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068                      |                                |
   | a=fingerprint:sha-1 99:41:49:83: | [RFC5245]                      |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07                |                                |
   | a=candidate:0 1 UDP  2113667327  | [RFC5245]                      |
   | 192.168.1.4 54609 typ host       |                                |
   | a=candidate:1 1 UDP  694302207 a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx    |                                |
   | raddr 192.168.1.4 rport 54609 :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | a=candidate:0 2 UDP 2113667326 :04 :BB:05:2F:70:9F:04:A9:0E:05:E | [RFC5245]                               |
   | 192.168.1.4 64678 typ host 9:26:33:E8:70:88:A2               |                               |
   | a=candidate:1 2 UDP  1694302206 a=setup:actpass                   | [RFC5245] [RFC4145]                     |
   | 24.23.204.141 64678 typ srflx a=rtcp-mux                        | [RFC5761]                     |
   | raddr 192.168.1.4 rport 64678 a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=ssrc:22222 a=extmap:2 urn:ietf:params:rtp-   | [RFC5576] [I-D.ietf-mmusic-sdp-bundle-n |
   | cname:Q/aoNWs11HmN4Xa5 hdrext:sdes:mid                   | egotiation]                   |
   | a=rtcp-rsize a=ssrc:56789                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            | [RFC5506]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                    Table 24: 23: 5.2.11 SDP Updated Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Updated Answer SDP Contents       | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=1                               | [RFC4566] Version number      |
   |                                   | incremented                   |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio video        | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:audio a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:c300d85b              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:de4e99bd291c325921d5d47 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendrecv efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:c300d85b a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 7efbabd9a2 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:54321                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 49203 51556 typ host        |                               |
   | a=candidate:1 1 UDP 1694302207    | [RFC5245]                     |
   | 98.248.92.77 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 49203    |                                |
   | a=ssrc:33333 raddr 192.168.1.7 rport 51556     | [RFC5576]                               |
   | cname:L/aoNWs11HmN4Xa5 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 120                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:video                       | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:video a=sendrecv                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:120 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=sendrecv                       | [RFC3264]                      |
   | a=setup:active                   | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=ice-ufrag:c300d85b             | [RFC5245]                      |
   | a=ice-pwd:de4e99bd291c325921d5d4 | [RFC5245]                      |
   | 7efbabd9a2                       |                                |
   | a=fingerprint:sha-1 99:41:49:83: a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | 9d:1f:66:79:a8:07                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | a=candidate:0 1 UDP 2113667327   | [RFC5245]                               |
   | 192.168.1.7 49203 typ host 1:58:D0:A1:2C:19:08               |                               |
   | a=candidate:1 1 UDP 1694302207 a=setup:active                    | [RFC5245] [RFC4145]                     |
   | 98.248.92.77 49203 typ srflx a=rtcp-mux                        | [RFC5761]                     |
   | raddr 192.168.1.7 rport 49203 a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:120 nack                | [RFC5104]                     |
   | a=rtcp-fb:120 nack pli            | [RFC5104]                     |
   | a=rtcp-fb:120 ccm fir             | [RFC5104]                     |
   | a=ssrc:44444 a=extmap:2 urn:ietf:params:rtp-   | [RFC5576] [I-D.ietf-mmusic-sdp-bundle-n |
   | cname:EocUG1f0fcg/yvY7 hdrext:sdes:mid                   | egotiation]                   |
   | a=rtcp-rsize a=ssrc:98765                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5            | [RFC5506]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                    Table 25: 24: 5.2.11 SDP Updated Answer

5.3.  MultiResolution, RTX, FEC Examples

   This section deals with scenarios related to multi-source, multi-
   stream negotiation such as layered coding, simulcast, along with
   techniques that deal with providing robustness against transmission
   errors such as FEC and RTX.  Also to note, mechanisms such as FEC and
   RTX could be envisioned in the above basic scenarios as well.

5.3.1.  Sendonly Simulcast Session with 2 cameras and 2 encodings per
        camera

   The SDP below shows Offer/Answer exchange with one audio and two
   video sources.  Each of the video source can be sent at two different
   resolutions.

   One video source corresponds to VP8 encoding, while the other
   corresponds to H.264 encoding.

   [I-D.ietf-mmusic-rid] framework is used to further constrain the
   media format encodings and map the payload types (PT) to the 'rid'
   identifiers.

   [I-D.ietf-mmusic-sdp-simulcast] framework identifies the simulcast
   streams via their 'rid' identifiers.

   bundle-only framework attribute is used along with for the video sources in the Offer to
   ensure enabling video sources in the context of BUNDLE alone.

   BUNDLE grouping framework to
   enable enables multiplexing of all the 5 streams
   (1 audio stream + 4 video streams) over a single RTP Session.

          1 Way Successful Simulcast w/BUNDLE

   Alice                                            Bob
   |                                                 |
   |                                                 |
   |     Alice offers 2 sendonly video sources       |
   |     with 2 simulcast encodings per source       |
   |           and bundle-only for video             |
   |                                                 |
   |                                                 |
   |   Offer(Audio:Opus,Video1:VP8,Video2:H.264)     |
   |------------------------------------------------>|
   |                                                 |
   |                                                 |
   |    Answer(Audio:Opus Video1:VP8,Video2:H.264)   |
   |<------------------------------------------------|
   |                                                 |
   |One-Way 1 Opus, 2 H.264 and 2 VP8 video streams, |
   | all multiplexed                                 |
   |.................................................|
   |                                                 |
   |                                                 |

   +-------------------------------------+-----------------------------+
   | Offer SDP Contents                  | RFC#/Notes                  |
   +-------------------------------------+-----------------------------+
   | v=0                                 | [RFC4566]                   |
   | o=- 20519 0 IN IP4 0.0.0.0          | [RFC4566]                   |
   | s=-                                 | [RFC4566]                   |
   | t=0 0                               | [RFC4566]                   |
   | a=msid-semantic:WMS ma              | [I-D.ietf-mmusic-msid]      |
   | a=group:BUNDLE m0 m1 m2             | [I-D.ietf-mmusic-sdp-bundle |
   |                                     | -negotiation] Alice         |
   |                                     | supports grouping of        |
   |                                     | m=lines under BUNDLE        |
   |                                     | semantics                   |
   | a=ice-options:trickle               | [I-D.ietf-mmusic-trickle-ic |
   |                                     | e]                          |
   | ****** Audio m=line *********       | *************************** |
   |                                     | **                          |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109 | [RFC4566]                   |
   | c=IN IP4 24.23.204.141              | [RFC4566]                   |
   | a=rtcp:54609 IN IP4 24.23.204.141   | [RFC3605]                   |
   | a=mid:m0                            | [RFC5888]                   |
   | a=msid:ma ta                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (ta) |
   | a=rtcp:64678 IN IP4 24.23.204.141   | [RFC3605]                   |
   | a=mid:m0 a=sendonly                          | [RFC5888] [RFC3264]                   |
   | a=rtpmap:109 opus/48000/2           | [I-D.ietf-payload-rtp-opus] |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                      | [RFC6464] [RFC4566]                   |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550                | [RFC5245]                   |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee3474 | [I-D.ietf-payload-rtp-opus] [RFC5245]                   |
   | a=sendonly af08a068                            |                             |
   | a=fingerprint:sha-256 19:E2:1C:3B:4 | [RFC5245]                   |
   | B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04  |                             |
   | :BB:05:2F:70:9F:04:A9:0E:05:E9:26:3 |                             |
   | 3:E8:70:88:A2                       | [RFC3264]                             |
   | a=setup:actpass                     | [RFC4145]                   |
   | a=rtcp-mux                          | [RFC5761]                   |
   | a=rtcp-fb:109 nack                  | [RFC5104]                   |
   | a=ssrc:11111 C90alEocUG1f0fcg a=rtcp-rsize                        | [RFC5576] [RFC5506]                   |
   | a=ice-ufrag:074c6550 a=rtcp-fb:109 nack                  | [RFC5245] [RFC5104]                   |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474 a=extmap:1 urn:ietf:params:rtp-     | [RFC5245] [RFC6464]                   |
   | af08a068 hdrext:ssrc-audio-level             |                             |
   | a=fingerprint:sha-1 99:41:49:83:4a: a=extmap:2 urn:ietf:params:rtp-     | [RFC5245] [I-D.ietf-mmusic-sdp-bundle |
   | 97:0e:1f:ef:6d:f7:c9:c7:70: hdrext:sdes:mid                     | -negotiation]               |
   | 9d:1f:66:79:a8:07 a=ssrc:11111 cname:EocUG1f0fcg/yvY7 | [RFC5576]                   |
   | a=candidate:0 1 UDP  2113667327     | [RFC5245]                   |
   | 192.168.1.4 54609 61665 typ host          |                             |
   | a=candidate:1 1 UDP  694302207      | [RFC5245]                   |
   | 24.23.204.141 54609 typ srflx raddr |                             |
   | 192.168.1.4 rport 54609 61665             |                             |
   | a=candidate:0 2 UDP 2113667326      | [RFC5245]                   |
   | 192.168.1.4 64678 typ host          |                             |
   | a=candidate:1 2 UDP  1694302206 a=end-of-candidates                 | [RFC5245] [I-D.ietf-mmusic-trickle-ic |
   | 24.23.204.141 64678 typ srflx raddr                                     | e]                          |
   | 192.168.1.4 rport 64678 ****** Video-1 m=line *********     | *************************** |
   | a=rtcp-rsize                                     | [RFC5506] **                          |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100  | bundle-only video line with |
   |                                     | port number set to zero     |
   | c=IN IP4 24.23.204.141              | [RFC4566]                   |
   | a=msid:ma tb                        | Identifies RTCMediaStream   |
   | a=bundle-only                       | ID (ma) and [I-D.ietf-mmusic-sdp-bundle |
   |                                     | RTCMediaStreamTrack ID (tb) -negotiation]               |
   | a=rtcp:64678 a=rtcp:54609 IN IP4 24.23.204.141   | [RFC3605]                   |
   | a=mid:m1                            | [RFC5888] Video m=line part |
   |                                     | of BUNDLE group             |
   | a=msid:ma tb                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (tb) |
   | a=sendonly                          | [RFC3264] - Send only video |
   |                                     | stream                      |
   | a=rtpmap:98 VP8/90000               | [I-D.ietf-payload-vp8]      |
   | a=fmtp:98 max-fr=30                 | [RFC4566]                   |
   | a=rtpmap:100 VP8/90000              | [I-D.ietf-payload-vp8]      |
   | a=fmtp:100 max-fr=15                | [RFC4566]                   |
   | a=rid:1 send pt=98;max-width=1280 a=fingerprint:sha-256 19:E2:1C:3B:4 | [I-D.ietf-mmusic-rid] 1:1 [RFC5245]                   |
   | ;max-height=720; B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04  | rid mapping to payload type                             |
   | :BB:05:2F:70:9F:04:A9:0E:05:E9:26:3 | and specify resolution                             |
   | 3:E8:70:88:A2                       | constraints                             |
   | a=rid:2 send pt=100;max-width=640 a=setup:actpass                     | [I-D.ietf-mmusic-rid] 1:1 [RFC4145]                   |
   | ;max-height=480; a=rtcp-mux                          | rid mapping to payload type [RFC5761]                   |
   | a=rtcp-mux-only                     | and specify resolution [I-D.ietf-mmusic-mux-exclus |
   |                                     | constraints ive]                        |
   | a=simulcast: send 1;~2 a=rtcp-rsize                        | [I-D.ietf-mmusic-sdp-simulc [RFC5506]                   |
   | a=rtcp-fb:* nack                    | ast] Alice can send 2 [RFC5104]                   |
   | a=rtcp-fb:* nack pli                | resolutions identified by [RFC5104]                   |
   | a=rtcp-fb:* ccm fir                 | the 'rid' identifiers Also, [RFC5104]                   |
   | a=extmap:2 urn:ietf:params:rtp-     | the second stream is [I-D.ietf-mmusic-sdp-bundle |
   | hdrext:sdes:mid                     | initially paused. -negotiation]               |
   | a=ssrc:12345 a=ssrc:22222 cname:EocUG1f0fcg/yvY7 | [RFC5576] [RFC7022]         |
   | cname:axzo1278npDlAzM73                                     | Camera-1,Encoding-1 SSRC    |
   |                                     | with Session CNAME          |
   | a=ssrc:45678 a=ssrc:33333 cname:EocUG1f0fcg/yvY7 | [RFC5576] [RFC7022]         |
   | cname:axzo1278npDlAzM73                                     | Camera-1,Encoding-2 SSRC    |
   |                                     | with Session CNAME          |
   | a=sendonly a=rid:1 send pt=98;max-width=1280   | [RFC3264] - Send only video [I-D.ietf-mmusic-rid] 1:1   |
   | ;max-height=720;                    | stream rid mapping to payload type |
   | a=rtcp-mux                                     | [RFC5761] and specify resolution      |
   | a=bundle-only                                     | [I-D.ietf-mmusic-sdp-bundle constraints                 |
   | a=rid:2 send pt=100;max-width=640   | -negotiation] [I-D.ietf-mmusic-rid] 1:1   |
   | a=rtcp-fb:98 nack ;max-height=480;                    | [RFC5104] rid mapping to payload type |
   | a=rtcp-fb:98 nack pli                                     | [RFC5104] and specify resolution      |
   | a=rtcp-fb:98 ccm fir                                     | [RFC5104] constraints                 |
   | a=rtcp-fb:100 nack a=simulcast: send 1;~2              | [RFC5104] [I-D.ietf-mmusic-sdp-simulc |
   | a=rtcp-fb:100 nack pli                                     | [RFC5104] ast] Alice can send 2       |
   | a=rtcp-fb:100 ccm fir                                     | [RFC5104] resolutions identified by   |
   | a=rtcp-rsize                                     | [RFC5506] the 'rid' identifiers Also, |
   |                                     | the second stream is        |
   |                                     | initially paused.           |
   | ****** Video-2 m=line *********     | *************************** |
   |                                     | **                          |
   | m=video 0 UDP/TLS/RTP/SAVPF 101 102 | bundle-only video line with |
   |                                     | port number set to zero     |
   | c=IN IP4 24.23.204.141 c=IN IP4 24.23.204.141              | [RFC4566]                   |
   | a=bundle-only                       | [I-D.ietf-mmusic-sdp-bundle |
   |                                     | -negotiation]               |
   | a=rtcp:54609 IN IP4 24.23.204.141   | [RFC3605]                   |
   | a=mid:m2                            | [RFC5888] Video m=line part |
   |                                     | [RFC4566] of BUNDLE group             |
   | a=msid:ma tc                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (tc) |
   | a=rtcp:64678 IN IP4 24.23.204.141   | [RFC3605]                   |
   | a=mid:m2 a=sendonly                          | [RFC5888] Video m=line part [RFC3264] - Send only video |
   |                                     | of BUNDLE group stream                      |
   | a=rtpmap:101 H264/90000             | [RFC3984]                   |
   | a=rtpmap:102 H264/90000             | [RFC3984]                   |
   | a=fmtp:101 profile-level-id=42401f  | [RFC3984]Camera-2,Encoding- |
   | ;packetization-mode=0;max-fr=30     | 1                           |
   | a=fmtp:102 profile-level-id=42401f  | [RFC3984]Camera-2,Encoding- |
   | ;packetization-mode=1;max-fr=15     | 2                           |
   | a=rid:3 send pt=101;max-width=1280 a=fingerprint:sha-256 19:E2:1C:3B:4 | [I-D.ietf-mmusic-rid] 1:1 [RFC5245]                   |
   | ;max-height=720; B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04  | rid mapping to payload type                             |
   | :BB:05:2F:70:9F:04:A9:0E:05:E9:26:3 | and specify resolution                             |
   | 3:E8:70:88:A2                       | constraints                             |
   | a=rid:4 send pt=102;max-width=640 a=setup:actpass                     | [I-D.ietf-mmusic-rid] 1:1 [RFC4145]                   |
   | ;max-height=360; a=rtcp-mux                          | rid mapping to payload type [RFC5761]                   |
   | a=rtcp-mux-only                     | and specify resolution [I-D.ietf-mmusic-mux-exclus |
   |                                     | constraints ive]                        |
   | a=simulcast: send 3;4 a=rtcp-rsize                        | [RFC5506]                   | [I-D.ietf-mmusic-sdp-simulc
   | a=rtcp-fb:* nack                    | [RFC5104]                   | ast] Alice can send 2
   | a=rtcp-fb:* nack pli                | [RFC5104]                   | resolutions identified by
   | a=rtcp-fb:*  ccm fir                | [RFC5104]                   | the 'rid' identifiers
   | a=extmap:2 urn:ietf:params:rtp-     | a=ssrc:67890 [I-D.ietf-mmusic-sdp-bundle |
   | hdrext:sdes:mid                     | -negotiation]               |
   | a=ssrc:44444 cname:EocUG1f0fcg/yvY7 | [RFC5576] [RFC7022]         |
   | cname:axzo1278npDlAzM73                                     | Camera-2,Encoding-1 SSRC    |
   |                                     | with Session CNAME          |
   | a=ssrc:56789 a=ssrc:55555 cname:EocUG1f0fcg/yvY7 | [RFC5576] [RFC7022]         |
   | cname:axzo1278npDlAzM73                                     | Camera-2,Encoding-2 SSRC    |
   |                                     | with Session CNAME          |
   | a=sendonly a=rid:3 send pt=101;max-width=1280  | [RFC3264] - Send only video [I-D.ietf-mmusic-rid] 1:1   |
   | ;max-height=720;                    | stream rid mapping to payload type |
   | a=rtcp-mux                                     | [RFC5761] and specify resolution      |
   | a=bundle-only                                     | [I-D.ietf-mmusic-sdp-bundle constraints                 |
   | a=rid:4 send pt=102;max-width=640   | -negotiation] [I-D.ietf-mmusic-rid] 1:1   |
   | a=rtcp-fb:101 nack ;max-height=360;                    | [RFC5104] rid mapping to payload type |
   | a=rtcp-fb:101 nack pli                                     | [RFC5104] and specify resolution      |
   | a=rtcp-fb:101  ccm fir                                     | [RFC5104] constraints                 |
   | a=rtcp-fb:102 nack a=simulcast: send 3;4               | [RFC5104] [I-D.ietf-mmusic-sdp-simulc |
   | a=rtcp-fb:102 nack pli                                     | [RFC5104] ast] Alice can send 2       |
   | a=rtcp-fb:102 ccm fir                                     | [RFC5104] resolutions identified by   |
   | a=rtcp-rsize                                     | [RFC5506] the 'rid' identifiers       |
   +-------------------------------------+-----------------------------+

                         Table 26: 25: 5.3.1 SDP Offer

   +-------------------------------------+-----------------------------+
   | Answer SDP Contents                 | RFC#/Notes                  |
   +-------------------------------------+-----------------------------+
   | v=0                                 | [RFC4566]                   |
   | o=- 20519 0 IN IP4 0.0.0.0          | [RFC4566]                   |
   | s=-                                 | [RFC4566]                   |
   | t=0 0                               | [RFC4566]                   |
   | a=msid-semantic:WMS ma              | [I-D.ietf-mmusic-msid]      |
   | a=group:BUNDLE m0 m1 m2             | [I-D.ietf-mmusic-sdp-bundle |
   |                                     | -negotiation] Alice         |
   |                                     | supports grouping of        |
   |                                     | m=lines under BUNDLE        |
   |                                     | semantics                   |
   | a=ice-options:trickle               | [I-D.ietf-mmusic-trickle-ic |
   |                                     | e]                          |
   | ****** Audio m=line *********       | *************************** |
   |                                     | **                          |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109 | [RFC4566]                   |
   | c=IN IP4 98.248.92.77               | [RFC4566]                   |
   | a=rtcp:60065 a=rtcp:49203 IN IP4 98.248.92.77    | [RFC3605]                   |
   | a=mid:m0                            | [RFC5888]                   |
   | a=msid:ma ta                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (ta) |
   | a=recvonly                          | [RFC3264]                   |
   | a=rtpmap:109 opus/48000/2           | [I-D.ietf-payload-rtp-opus] |
   | a=extmap:1 urn:ietf:params:rtp- a=rtcp-fb:109 nack                  | [RFC6464] [RFC5104]                   |
   | hdrext:ssrc-audio-level a=maxptime:120                      | [RFC4566]                   |
   | a=rtcp-fb:109 nack a=ice-ufrag:c300d85b                | [RFC5104] [RFC5245]                   |
   | a=ptime:20 a=ice-pwd:de4e99bd291c325921d5d47ef | [I-D.ietf-payload-rtp-opus] [RFC5245]                   |
   | a=recvonly babd9a2                             | [RFC3264]                             |
   | a=setup:active a=fingerprint:sha-256 6B:8B:F0:65:5 | [RFC4145] [RFC5245]                   |
   | a=rtcp-mux F:78:E2:51:3B:AC:6F:F3:3F:46:1B:35  | [RFC5761]                             |
   | a=ssrc:22222 :DC:B8:5F:64:1A:24:C2:43:F0:A1:58:D | [RFC5576]                             |
   | cname:y8/C90alEocUG1f0fcg 0:A1:2C:19:08                       |                             |
   | a=ice-ufrag:c300d85b a=setup:active                      | [RFC5245] [RFC4145]                   |
   | a=ice-pwd:de4e99bd291c325921d5d47ef a=rtcp-mux                          | [RFC5245] [RFC5761]                   |
   | babd9a2 a=rtcp-rsize                        | [RFC5506]                   |
   | a=extmap:1 urn:ietf:params:rtp-     | [RFC6464]                   | a=fingerprint:sha-1 99:41:49:83:4a:
   | [RFC5245] hdrext:ssrc-audio-level             |                             |
   | a=extmap:2 urn:ietf:params:rtp-     | [I-D.ietf-mmusic-sdp-bundle |
   | 97:0e:1f:ef:6d:f7:c9:c7:70: hdrext:sdes:mid                     | -negotiation]               |
   | 9d:1f:66:79:a8:07 a=ssrc:77777 cname:Q/NWs1ao1HmN4Xa5 | [RFC5576]                   |
   | a=candidate:0 2 1 UDP  2113667327     | [RFC5245]                   |
   | 192.168.1.7 49203 61665 typ host          |                             |
   | a=candidate:1 2 1 UDP  694302207      | [RFC5245]                   |
   | 98.248.92.77 49203 typ srflx raddr  |                             |
   | 192.168.1.4 rport 49203 61665             |                             |
   | a=rtcp-rsize a=end-of-candidates                 | [I-D.ietf-mmusic-trickle-ic |
   |                                     | e]                          |
   | ****** Video-1 m=line *********     | *************************** | [RFC5506]
   |                                     | **                          |
   | m=video 49203 UDP/TLS/RTP/SAVPF 98  | BUNDLE accepted with port   |
   | 100                                 | repeated from the audio     |
   |                                     | port                        |
   | c=IN IP4 98.248.92.77               | [RFC4566]                   |
   | a=rtcp:49203 IN IP4 98.248.92.77    | [RFC3605]                   |
   | a=mid:m1                            | [RFC5888] Video m=line part |
   |                                     | of BUNDLE group             |
   | a=msid:ma tb                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (tb) |
   | a=rtcp:60065 IN IP4 98.248.92.77    | [RFC3605]                   |
   | a=mid:m1 a=recvonly                          | [RFC5888] Video m=line part [RFC3264] - receive only    |
   |                                     | of BUNDLE group video stream                |
   | a=rtpmap:98 VP8/90000               | [I-D.ietf-payload-vp8]      |
   | a=rtpmap:100 VP8/90000              | [I-D.ietf-payload-vp8]      |
   | a=fmtp:98 max-fr=30                 | [RFC4566]                   |
   | a=fmtp:100 max-fr=15                | [RFC4566]                   |
   | a=rid:1 recv pt=98;max-width=1280   | [I-D.ietf-mmusic-rid] Bob   |
   | ;max-height=720;                    | accepts the offered payload |
   | a=fingerprint:sha-256 6B:8B:F0:65:5 | format constraints [RFC5245]                   |
   | a=rid:2 recv pt=100;max-width=640 F:78:E2:51:3B:AC:6F:F3:3F:46:1B:35  | [I-D.ietf-mmusic-rid] Bob                             |
   | ;max-height=480; :DC:B8:5F:64:1A:24:C2:43:F0:A1:58:D | accepts the offered payload                             |
   | 0:A1:2C:19:08                       | format constraints                             |
   | a=simulcast: recv 1;2 a=setup:active                      | [I-D.ietf-mmusic-sdp-simulc [RFC4145]                   |
   | a=rtcp-mux                          | ast] Bob accepts the [RFC5576]                   |
   | a=rtcp-rsize                        | offered simulcast streams [RFC5506]                   |
   | a=rtcp-fb:* nack                    | and removes the paused [RFC5104]                   |
   | a=rtcp-fb:* nack pli                | state of stream with 'rid' [RFC5104]                   |
   | a=rtcp-fb:* ccm fir                 | value 2. [RFC5104]                   |
   | a=recvonly a=extmap:2 urn:ietf:params:rtp-     | [RFC3264] - receive only [I-D.ietf-mmusic-sdp-bundle |
   | hdrext:sdes:mid                     | video stream -negotiation]               |
   | a=ssrc:54321 a=ssrc:88888 cname:Q/NWs1ao1HmN4Xa5 | [RFC5576] - SSRC associated |
   | cname:y8/C90alEocUG1f0fcg           |                             |
   | a=ice-ufrag:c300d85b                                     | [RFC5245] with the receiver report    |
   | a=ice-pwd:de4e99bd291c325921d5d47ef                                     | [RFC5245] from Bob                    |
   | babd9a2 a=rid:1 recv pt=98;max-width=1280   | [I-D.ietf-mmusic-rid] Bob   |
   | a=fingerprint:sha-1 99:41:49:83:4a: ;max-height=720;                    | [RFC5245] accepts the offered payload |
   | 97:0e:1f:ef:6d:f7:c9:c7:70:9d:                                     | format constraints          |
   | 1f:66:79:a8:07 a=rid:2 recv pt=100;max-width=640   | [I-D.ietf-mmusic-rid] Bob   |
   | a=candidate:0 2 UDP 2113667326 ;max-height=480;                    | [RFC5245] accepts the offered payload |
   | 192.168.1.7 60065 typ host                                     | format constraints          |
   | a=candidate:1 2 UDP  1694302206 a=simulcast: recv 1;2               | [RFC5245] [I-D.ietf-mmusic-sdp-simulc |
   | 98.248.92.77 60065 typ srflx raddr                                     | ast] Bob accepts the        |
   | 192.168.1.4 rport 60065                                     | offered simulcast streams   |
   | a=setup:active                                     | [RFC4145] and removes the paused      |
   | a=rtcp-mux                                     | [RFC5576] state of stream with 'rid'  |
   | a=bundle-only                                     | [I-D.ietf-mmusic-sdp-bundle value 2.                    |
   | ****** Video-2 m=line *********     | -negotiation] *************************** |
   | a=rtcp-rsize                                     | [RFC5506] **                          |
   | m=video 49203 UDP/TLS/RTP/SAVPF 101 | BUNDLE accepted with port   |
   | 102                                 | repeated from the audio     |
   |                                     | port                        |
   | c=IN IP4 98.248.92.77               | [RFC4566]                   |
   | a=rtcp:56503 a=rtcp:49203 IN IP4 98.248.92.77    | [RFC3605] [RFC3605]                   |
   | a=mid:m2                            | [RFC5888] Video m=line part |
   |                                     | of BUNDLE group             |
   | a=msid:ma tc                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (tc) |
   | a=mid:m2                            | [RFC5888] Video m=line part |
   | a=recvonly                          | of BUNDLE group [RFC3264]                   |
   | a=rtpmap:101 H264/90000             | [RFC3984]                   |
   | a=rtpmap:102 H264/90000             | [RFC3984]                   |
   | a=recvonly                          | [RFC3264]                   |
   | a=fmtp:101 profile-level-id=42401f  | [RFC3984]                   |
   | ;packetization-mode=1;max-fr=30     |                             |
   | a=fmtp:102 profile-level-id=42401f  | [RFC3984]                   |
   | ;packetization-mode=1;max-fr=15     |                             |
   | a=rid:3 recv pt=101;max-width=1280  | [I-D.ietf-mmusic-rid] Bob   |
   | ;max-height=720;                    | accepts the offered payload |
   |                                     | format constraints          |
   | a=rid:4 recv pt=102;max-width=640 a=fingerprint:sha-256 6B:8B:F0:65:5 | [I-D.ietf-mmusic-rid] Bob [RFC5245]                   |
   | ;max-height=360; F:78:E2:51:3B:AC:6F:F3:3F:46:1B:35  | accepts the offered payload                             |
   | :DC:B8:5F:64:1A:24:C2:43:F0:A1:58:D | format constraints                             |
   | a=simulcast: recv 3;4 0:A1:2C:19:08                       | [I-D.ietf-mmusic-sdp-simulc                             |
   | a=setup:active                      | ast] Bob accepts the [RFC4145]                   |
   | a=rtcp-mux                          | offered simulcast streams. [RFC5576]                   |
   | a=ssrc:90876 a=rtcp-rsize                        | [RFC5576] [RFC5506]                   |
   | cname:axzo1278npDlAzM73 a=rtcp-fb:* nack                    | [RFC5104]                   |
   | a=ice-ufrag:ufrag:c300d85b a=rtcp-fb:* nack pli                | [RFC5245] [RFC5104]                   |
   | a=ice-pwd:de4e99bd291c325921d5d47ef a=rtcp-fb:*  ccm fir                | [RFC5245] [RFC5104]                   |
   | babd9a2 a=extmap:2 urn:ietf:params:rtp-     | [I-D.ietf-mmusic-sdp-bundle |
   | a=fingerprint:sha-1 99:41:49:83:4a: hdrext:sdes:mid                     | [RFC5245] -negotiation]               |
   | 97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:99999 cname:Q/NWs1ao1HmN4Xa5 | [RFC5576] - SSRC associated |
   | 9d:1f:66:79:a8:07                                     | with the receiver report    |
   | a=candidate:0 2 UDP 2113667326                                     | [RFC5245] from Bob                    |
   | 192.168.1.7 60065 typ host a=rid:3 recv pt=101;max-width=1280  | [I-D.ietf-mmusic-rid] Bob   |
   | a=candidate:1 2 UDP  1694302206 ;max-height=720;                    | [RFC5245] accepts the offered payload |
   | 98.248.92.77 60065 typ srflx raddr                                     | format constraints          |
   | 192.168.1.7 rport 60065 a=rid:4 recv pt=102;max-width=640   | [I-D.ietf-mmusic-rid] Bob   |
   | a=setup:active ;max-height=360;                    | [RFC4145] accepts the offered payload |
   | a=rtcp-mux                                     | [RFC5576] format constraints          |
   | a=bundle-only a=simulcast: recv 3;4               | [I-D.ietf-mmusic-sdp-bundle [I-D.ietf-mmusic-sdp-simulc |
   |                                     | -negotiation] ast] Bob accepts the        |
   | a=rtcp-rsize                                     | [RFC5506] offered simulcast streams.  |
   +-------------------------------------+-----------------------------+

                        Table 27: 26: 5.3.1 SDP Answer

5.3.2.  Successful SVC Video Session

   This section shows an SDP Offer/Answer for a session with an audio
   and a single video source.  The video source is encoded as layered
   coding at 3 different resolutions based on [RFC5583].  The video
   m=line shows 3 streams with last stream (payload 100) dependent on
   streams with payload 96 and 97 for decoding.

          SVC Session - 3 Layers w/BUNDLE

  Alice                                            Bob
  |                                                 |
  |                                                 |
  |      Alice offers 3 sendonly video streams      |
  |      as 3 layers of SVC and bundle-only         |
  |               for video streams.                |
  |                                                 |
  |            Offer(Video:H.264 SVC)               |
  |------------------------------------------------>|
  |                                                 |
  |                                                 |Bob accepts Alice's
  |                                                 |offered Codec
  |                                                 |operation points
  |                                                 |
  |             Answer(Video:H.264)                 |
  |<------------------------------------------------|
  |                                                 |
  |One-Way  H.264 SVC video streams                 |
  |.................................................|
  |                                                 |
  |                                                 |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice supports    |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=msid:ma ta                     | Identifies RTCMediaStream ID   |
   |                                  | (ma) and RTCMediaStreamTrack   |
   |                                  | ID (ta)                        |
   | a=rtcp:64678 a=rtcp:54609 IN IP4              | [RFC3605]                      |
   | 24.23.204.141 | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888] Audio m=line part of   |
   |                                   | of BUNDLE group with a unique |
   |                                   | port number                   |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=sendonly                        | [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee34 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=sendonly 74af08a068                        | [RFC3264]                               |
   | a=rtcp-fb:109 nack a=fingerprint:sha-256 19:E2:1C:3B | [RFC5104] [RFC5245]                     |
   | a=setup:actpass :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | [RFC4145]                               |
   | a=rtcp-mux :04 :BB:05:2F:70:9F:04:A9:0E:05:E | [RFC5761]                               |
   | a=ice-ufrag:074c6550 9:26:33:E8:70:88:A2               | [RFC5245]                               |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=setup:actpass                   | [RFC5245] [RFC4145]                     |
   | 474af08a068 a=rtcp-mux                        | [RFC5761]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=rtcp-fb:109 nack                | [RFC5104]                     |
   | 9d:1f:66:79:a8:07 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=candidate:0 1 UDP  2113667327 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 192.168.1.4 54609 typ host a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=candidate:1 1 UDP  694302207 hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 24.23.204.141 54609 typ srflx a=ssrc:11111                      | [RFC5576]                     |
   | raddr 192.168.1.4 rport 54609 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326  2113667327   | [RFC5245]                     |
   | 192.168.1.4 64678 61665 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206  694302207    | [RFC5245]                     |
   | 24.23.204.141 64678 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 64678    |                                |
   | a=ssrc:67890 61665     | [RFC5576]                               |
   | cname:axzo1278npDlAzM73 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 0 UDP/TLS/RTP/SAVPF 96 97 | bundle-only video line with   |
   | 97 100                               | port number set to zero       |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=msid:ma tb                     | Identifies RTCMediaStream ID   |
   | a=bundle-only                     | (ma) and RTCMediaStreamTrack [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | ID (tc) egotiation]                   |
   | a=rtcp:64678 a=rtcp:54609 IN IP4              | [RFC3605]                      |
   | 24.23.204.141 | [RFC3605]                     |
   | a=mid:m1                          | [RFC5888] Audio Video m=line part of   |
   |                                   | of BUNDLE group               |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tc)                       |
   | a=sendonly                        | [RFC3264] - Send only video   |
   |                                   | stream                        |
   | a=rtpmap:96 H264/90000            | [RFC3984]                     |
   | a=fmtp:96 profile-level-          | [RFC3984]H.264 Layer 1        |
   | id=4d0028; packetization-mode=1   |                               |
   | ;max-fr=30;max-fs=8040            |                               |
   | a=rtpmap:97 H264/90000            | [RFC3984]                     |
   | a=fmtp:97 profile-level- profile-level-id=4d0028 | [RFC3984] H.264 Layer 2       |
   | id=4d0028;packetization-mode=1; ;packetization-mode=1; max-fr=15  |                               |
   | max-fr=15;max-fs=1200 ;max-fs=1200                      |                               |
   | a=rtpmap:100 H264-SVC/90000       | [RFC3984]                     |
   | a=fmtp:100 profile-level-         | [RFC3984]                     |
   | id=4d0028;packetization-mode=1;   |                               |
   | max-fr=30;max-fs=8040             |                               |
   | a=depend:100 lay m1:96,97;        | [RFC5583]Layer 3 dependent on |
   |                                   | layers 1 and 2                |
   | a=sendonly a=fingerprint:sha-256 19:E2:1C:3B | [RFC3264] - Send only video [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               |                               | stream
   | a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=bundle-only a=rtcp-rsize                      | [I-D.ietf-mmusic-sdp-bundle-ne [RFC5506]                     |
   | a=rtcp-fb:* nack                  | gotiation] [RFC5104]                     |
   | a=ssrc:1732846380 a=rtcp-fb:* nack pli              | [RFC5576] [RFC5104]                     |
   | cname:axzo1278npDlAzM73 a=rtcp-fb:* ccm fir               | [RFC5104]                     |
   | a=ssrc:1732846381 a=extmap:2 urn:ietf:params:rtp-   | [RFC5576] [I-D.ietf-mmusic-sdp-bundle-n |
   | cname:axzo1278npDlAzM73 hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:1732846382 a=ssrc:22222                      | [RFC5576]                     |
   | cname:axzo1278npDlAzM73 cname:EocUG1f0fcg/yvY7            |                               |
   | a=rtcp-fb:* nack a=ssrc:33333                      | [RFC5104] [RFC5576]                     |
   | a=rtcp-fb:* nack pli cname:EocUG1f0fcg/yvY7            | [RFC5104]                               |
   | a=rtcp-fb:* ccm fir a=ssrc:44444                      | [RFC5104] [RFC5576]                     |
   | a=rtcp-rsize cname:EocUG1f0fcg/yvY7            | [RFC5506]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                    Table 28: 27: 5.3.2 SDP Offer with SVC

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:m0 a=recvonly                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee34 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=rtcp-fb:109 nack 74af08a068                        | [RFC5104]                               |
   | a=recvonly a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 474af08a068 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:88888                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 2 1 UDP 2113667326    | [RFC5245]                     |
   | 192.168.1.7 60065 51556 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206   | [RFC5245]                     |
   | 98.248.92.77 60065 49203 typ srflx      |                               |
   | raddr 192.168.1.5 rport 60065 51556     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | ****** Video m=line *********     | ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | BUNDLE accepted Bundle address        |
   | 96 100                            | address same as audio m=line. |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m1                          | [RFC5888] Video m=line part   |
   |                                   | of BUNDLE group               |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp:56503 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:m1 a=recvonly                        | [RFC5888] Video m=line part of [RFC3264] - Receive only      |
   |                                   | BUNDLE group video stream                  |
   | a=rtpmap:96 H264/90000            | [RFC3984]                     |
   | a=fmtp:96 profile-level- profile-level-id=4d0028 | [RFC3984]H.264 Layer 1        |
   | id=4d0028;packetization-mode=1; ;packetization-mode=1; max-fr=30  |                               |
   | max-fr=30;max-fs=8040 ;max-fs=8040                      |                               |
   | a=rtpmap:100 H264-SVC/90000       | [RFC3984]                     |
   | a=fmtp:100 profile-level-         | [RFC3984]                     |
   | id=4d0028;packetization-mode=1;   |                               |
   | max-fr=30;max-fs=8040             |                               |
   | a=depend:100 lay m1:96;           | [RFC5583] Bob chooses 2 Codec |
   |                                   | Operation points              |
   | a=ice-ufrag:074c6550             | [RFC5245]                      |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 | [RFC5245]                      |
   | 474af08a068                      |                                |
   | a=fingerprint:sha-1 99:41:49:83: a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:   |                                |
   | 9d:1f:66:79:a8:07 :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | a=candidate:0 2 UDP 2113667326   | [RFC5245]                      |
   | 192.168.1.5 64678 typ host :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | a=candidate:1 2 UDP  1694302206 1:58:D0:A1:2C:19:08               | [RFC5245]                               |
   | 24.23.204.142 64678 typ srflx a=setup:active                    | [RFC4145]                     |
   | raddr 192.168.1.5 rport 64678 a=rtcp-mux                        | [RFC5761]                     |
   | a=recvonly a=rtcp-rsize                      | [RFC3264] - Receive only video [RFC5506]                     |
   | a=rtcp-fb:* nack                  | stream [RFC5104]                     |
   | a=setup:active a=rtcp-fb:* nack pli              | [RFC4145] [RFC5104]                     |
   | a=rtcp-mux a=rtcp-fb:* ccm fir               | [RFC5761] [RFC5104]                     |
   | a=bundle-only a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | gotiation] egotiation]                   |
   | a=ssrc:4638117328 a=ssrc:99999                      | [RFC5576]                     |
   | cname:axzo1278npDlAzM73          |                                |
   | a=rtcp-rsize cname:Q/NWs1ao1HmN4Xa5            | [RFC5506]                               |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                    Table 29: 28: 5.3.2 SDP Answer with SVC

5.3.3.  Successful Simulcast Video Session with Retransmission

   This section shows an SDP Offer/Answer exchange for a simulcast
   scenario with 3 resolutions and has [RFC4588] style re-transmission
   flows.

   [I-D.ietf-mmusic-rid] framework is used to specify all the (3)
   resolution constraints mapped to a single Payload Type (98).

   [I-D.ietf-mmusic-sdp-simulcast] framework identifies the simulcast
   streams via their 'rid' identifiers.

           Simulcast Streams with Retransmission

   Alice                                                    Bob
   |                                                         |
   |                                                         |
   |Alice offers single audio and simulcasted video streams  |
   |                                                         |
   |                                                         |
   |    Offer(Audio:Opus Video:VP8 with 3 resolutions)       |
   |    & RTX stream                                         |
   |-------------------------------------------------------->|
   |                                                         |
   |                                                         |
   |          Answer (Bob accepts Alice's offer)             |
   |<--------------------------------------------------------|
   |                                                         |
   |                                                         |
   |One-Way 1 Opus, 3 VP8 and RTX video streams,all muxed    |
   |.........................................................|
   |                                                         |
   |                                                         |
   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice supports    |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=msid:ma ta                     | Identifies RTCMediaStream ID   |
   |                                  | (ma) and RTCMediaStreamTrack   |
   |                                  | ID (ta)                        |
   | a=rtcp:64678 a=rtcp:54609 IN IP4              | [RFC3605]                      |
   | 24.23.204.141 | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888] Audio m=line part of   |
   |                                   | of BUNDLE group with a unique |
   |                                   | port number                   |
   | a=rtpmap:109 opus/48000/2 a=msid:ma ta                      | [I-D.ietf-payload-rtp-opus] Identifies RTCMediaStream ID  |
   | a=extmap:1 urn:ietf:params:rtp-                                   | [RFC6464] (ma) and RTCMediaStreamTrack  |
   | hdrext:ssrc-audio-level                                   | ID (ta)                       |
   | a=sendonly                        | a=ptime:20 [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=rtcp-fb:109 nack a=maxptime:120                    | [RFC5104] [RFC4566]                     |
   | a=sendonly a=ice-ufrag:074c6550              | [RFC3264] [RFC5245]                     |
   | a=setup:actpass a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC4145] [RFC5245]                     |
   | a=rtcp-mux 74af08a068                        | [RFC5761]                               |
   | a=ssrc:11111 a=fingerprint:sha-256 19:E2:1C:3B | [RFC5576] [RFC5245]                     |
   | cname:EocUG1f0fcg/yvY7 :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | a=ice-ufrag:074c6550 :04 :BB:05:2F:70:9F:04:A9:0E:05:E | [RFC5245]                               |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 9:26:33:E8:70:88:A2               | [RFC5245]                               |
   | 474af08a068 a=setup:actpass                   | [RFC4145]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=rtcp-mux                        | [RFC5245] [RFC5761]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7: a=rtcp-rsize                      | [RFC5506]                     |
   | 70:9d:1f:66:79:a8:07 a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=candidate:0 1 UDP  2113667327 a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | 192.168.1.4 54609 typ host hdrext:ssrc-audio-level           |                               |
   | a=candidate:1 1 UDP  694302207 a=extmap:2 urn:ietf:params:rtp-   | [RFC5245] [I-D.ietf-mmusic-sdp-bundle-n |
   | 24.23.204.141 54609 typ srflx hdrext:sdes:mid                   | egotiation]                   |
   | raddr 192.168.1.4 rport 54609 a=ssrc:11111                      | [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326  2113667327   | [RFC5245]                     |
   | 192.168.1.4 64678 61665 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206  694302207    | [RFC5245]                     |
   | 24.23.204.141 64678 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 64678 61665     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | ****** Video m=line *********     | ***************************** |
   | m=video 0 UDP/TLS/RTP/SAVPF 98    | bundle-only video line with   |
   | 103                               | port number set to zero       |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=bundle-only                     | [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | a=mid:m1                          | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp:64678 IN IP4              | [RFC3605]                      |
   | 24.23.204.141                    |                                |
   | a=mid:m1 a=sendonly                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:98 VP8/90000             | [I-D.ietf-payload-vp8]        |
   | a=fmtp:98 max-fr=30;max-fs=3600 max-fr=30               | [RFC4566]                     |
   | a=rtpmap:103 rtx/90000            | [RFC4588]                     |
   | a=fmtp:103 apt=98;rtx-time=200    | [RFC4588]                     |
   | a=rid:1 send pt=98;max-fs=921600 a=setup:actpass                   | [I-D.ietf-mmusic-rid] [RFC4145]                     |
   | ;max-fr=30; a=rtcp-mux                        | [RFC5761]                     |
   | a=rid:2 send pt=98;max-fs=614400 a=rtcp-rsize                      | [I-D.ietf-mmusic-rid] [RFC5506]                     |
   | ;max-fr=15; a=rtcp-fb:* nack                  | [RFC5104]                     |
   | a=rid:3 send pt=98;max-fs=230400 a=rtcp-fb:* nack pli              | [I-D.ietf-mmusic-rid] [RFC5104]                     |
   | ;max-fr=30; a=rtcp-fb:* ccm fir               | [RFC5104]                     |
   | a=simulast: send 5;6;7 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-simulcast [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | ] Alice can send all the egotiation]                   |
   | a=ssrc:22222                      | simulcast streams [RFC5576] - Encoding-1 SSRC   |
   | a=ssrc-group:FID 12345 34567 cname:EocUG1f0fcg/yvY7            | [RFC5888]                               |
   | a=ssrc:33333                      | [RFC5576] - Encoding-1 RTX    |
   | cname:EocUG1f0fcg/yvY7            | SSRC                          |
   | a=ssrc-group:FID 78990 90887 22222 33333      | [RFC5888]                     |
   | a=ssrc:12345 a=ssrc:44444                      | [RFC5576] - Encoding-2 SSRC   |
   | cname:Q/NWs1ao1HmN4Xa5 cname:EocUG1f0fcg/yvY7            |                               |
   | a=ssrc:78990 a=ssrc:55555                      | [RFC5576] - Encoding-2 RTX    |
   | cname:Q/NWs1ao1HmN4Xa5 cname:EocUG1f0fcg/yvY7            | SSRC                          |
   | a=ssrc-group:FID 44444 55555      | [RFC5888]                     |
   | a=ssrc:34567 a=ssrc:66666                      | [RFC5576] - Encoding-3 SSRC   |
   | cname:Q/NWs1ao1HmN4Xa5 cname:EocUG1f0fcg/yvY7            |                               |
   | a=ssrc:90887 a=ssrc:77777                      | [RFC5576] - Encoding-3 RTX    |
   | cname:Q/NWs1ao1HmN4Xa5 cname:EocUG1f0fcg/yvY7            | SSRC                          |
   | a=sendonly a=ssrc-group:FID 66666 77777      | [RFC3264] [RFC5888]                     |
   | a=rtcp-mux a=rid:1 send pt=98;max-fs=921600  | [RFC5761] [I-D.ietf-mmusic-rid]         |
   | a=bundle-only ;max-fr=30;                       | [I-D.ietf-mmusic-sdp-bundle-ne                               |
   | a=rid:2 send pt=98;max-fs=614400  | gotiation] [I-D.ietf-mmusic-rid]         |
   | a=rtcp-fb:* nack ;max-fr=15;                       | [RFC5104]                               |
   | a=rtcp-fb:* nack pli a=rid:3 send pt=98;max-fs=230400  | [RFC5104] [I-D.ietf-mmusic-rid]         |
   | a=rtcp-fb:* ccm fir ;max-fr=30;                       | [RFC5104]                               |
   | a=rtcp-rsize a=simulcast: send 1;2;3           | [I-D.ietf-mmusic-sdp-simulcas | [RFC5506]
   |
   +----------------------------------+--------------------------------+                                   | t] Alice can send all the     |
   |                                   | simulcast streams             |
   +-----------------------------------+-------------------------------+

                Table 30: 29: 5.3.3 SDP Offer w/Simulcast, RTX

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Bob supports      |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:m0 a=recvonly                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC4566]                     |
   | a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245]                     |
   | 74af08a068                        | [RFC6464]                               |
   | hdrext:ssrc-audio-level a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | a=ptime:20 :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | [I-D.ietf-payload-rtp-opus]                               |
   | a=rtcp-fb:109 nack :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [RFC5104]                               |
   | a=recvonly 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ssrc:33333 a=rtcp-rsize                      | [RFC5576] [RFC5506]                     |
   | cname:L/HmN4Xa5NWs1ao1 a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:074c6550 a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 474af08a068 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:54321                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326    | [RFC5245]                     |
   | 192.168.1.7 64678 51556 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206   | [RFC5245]                     |
   | 98.248.92.77 64678 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 60065 51556     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | ****** Video m=line *********     | ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | BUNDLE accepted with Bundle   |
   | 98 100 101 103                    | address identical to audio    |
   |                                   | m-line                        |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m1                          | [RFC5888] Video m=line part   |
   |                                   | of BUNDLE group               |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:m1                         | [RFC5888] Video m=line part of |
   | a=recvonly                        | BUNDLE group [RFC3264]                     |
   | a=rtpmap:98 VP8/90000             | [I-D.ietf-payload-vp8]        |
   | a=fmtp:98 max-fr=30;max-fs=3600 max-fr=30               | [RFC4566]                     |
   | a=rtpmap:103 rtx/90000            | [RFC4588]                     |
   | a=fmtp:103 apt=98;rtx-time=200    | [RFC4588]                     |
   | a=rid:1 recv pt=98;max-fs=921600 a=fingerprint:sha-256 6B:8B:F0:65 | [I-D.ietf-mmusic-rid] [RFC5245]                     |
   | ;max-fr=30; :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | a=rid:2 recv pt=98;max-fs=614400 :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [I-D.ietf-mmusic-rid]                               |
   | ;max-fr=15; 1:58:D0:A1:2C:19:08               |                               |
   | a=rid:3 recv pt=98;max-fs=230400 a=setup:active                    | [I-D.ietf-mmusic-rid] [RFC4145]                     |
   | ;max-fr=30; a=rtcp-mux                        | [RFC5761]                     |
   | a=simulast: recv 5;6;7 a=rtcp-rsize                      | [I-D.ietf-mmusic-sdp-simulcast [RFC5506]                     |
   | a=rtcp-fb:* nack                  | ] Bob accepts the offered [RFC5104]                     |
   | a=rtcp-fb:* nack pli              | simulcast streams [RFC5104]                     |
   | a=ice-ufrag:074c6550 a=rtcp-fb:* ccm fir               | [RFC5245] [RFC5104]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=extmap:2 urn:ietf:params:rtp-   | [RFC5245] [I-D.ietf-mmusic-sdp-bundle-n |
   | 474af08a068 hdrext:sdes:mid                   | egotiation]                   |
   | a=fingerprint:sha-1 99:41:49:83: a=ssrc:98765                      | [RFC5245] [RFC5576]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7: cname:EocUG1f0fcg/yvY7            |                               |
   | 70:9d:1f:66:79:a8:07 a=rid:1 recv pt=98;max-fs=921600  | [I-D.ietf-mmusic-rid]         |
   | a=candidate:0 2 UDP 2113667326 ;max-fr=30;                       | [RFC5245]                               |
   | 192.168.1.7 60065 typ host a=rid:2 recv pt=98;max-fs=614400  | [I-D.ietf-mmusic-rid]         |
   | a=candidate:1 2 UDP  1694302206 ;max-fr=15;                       | [RFC5245]                               |
   | 98.248.92.772 60065 typ srflx a=rid:3 recv pt=98;max-fs=230400  | [I-D.ietf-mmusic-rid]         |
   | raddr 192.168.1.7 rport 60065 ;max-fr=30;                       |                               |
   | a=simulcast: recv 98;100         | [I-D.ietf-mmusic-sdp-simulcast |
   |                                  | ]                              |
   | a=recvonly                       | [RFC3264]                      |
   | a=setup:active                   | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=bundle-only                    | [I-D.ietf-mmusic-sdp-bundle-ne |
   |                                  | gotiation]                     |
   | a=rtcp-fb:* nack                 | [RFC5104]                      |
   | a=rtcp-fb:* nack pli 1;2;3           | [RFC5104] [I-D.ietf-mmusic-sdp-simulcas |
   | a=rtcp-fb:* ccm fir                                   | [RFC5104] t] Bob accepts the offered    |
   | a=rtcp-rsize                                   | [RFC5506] simulcast streams             |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                Table 31: 30: 5.3.3 SDP Answer w/Simulcast, RTX

5.3.4.  Successful 1-way Simulcast Session with 2 resolutions and RTX -
        One resolution rejected

   This section shows an SDP Offer/Answer exchange for a simulcast
   scenario with 2 two resolutions.

   It also showcases when where Bob rejects one of the Simulcast Video Stream
   which results in the rejection of the associated repair stream
   implicitly.

     Simulcast Streams with Retransmission Rejected

Alice                                                    Bob
|                                                         |
|                                                         |
|Alice offers single audio and simulcasted video streams  |
| with bundle-only for video                              |
|                                                         |
|                                                         |
|Offer(Audio:Opus Video:VP8 with 2 resolutions,RTX Stream)|
|-------------------------------------------------------->|
|                                                         |
|                                                         |Bob accepts 1
|                                                         |simulcast,rtx
|                                                         |rejects the
|                                                         |other
|   Answer(Audio:Opus Video:VP8 with 1 res & RTX Stream)  |
|<--------------------------------------------------------|
|                                                         |
|                                                         |
|1-way audio,video session and its associated RTX stream, |
| all multiplexed                                         |
|.........................................................|
|                                                         |
|                                                         |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice supports    |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta) ID (ta)                       |
   | a=sendonly                        | [RFC3264]                     |
   | a=rtcp:64678 IN IP4 a=rtpmap:109 opus/48000/2         | [RFC3605] [I-D.ietf-payload-rtp-opus]   |
   | 24.23.204.141 a=maxptime:120                    | [RFC4566]                     |
   | a=mid:m0 a=ice-ufrag:074c6550              | [RFC5888] [RFC5245]                     |
   | a=rtpmap:109 opus/48000/2 a=ice-pwd:a28a397a4c3f31747d1ee34 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=extmap:1 urn:ietf:params:rtp- 74af08a068                        | [RFC6464]                               |
   | hdrext:ssrc-audio-level a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | a=ptime:20 :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | [I-D.ietf-payload-rtp-opus]                               |
   | a=rtcp-fb:109 nack :04 :BB:05:2F:70:9F:04:A9:0E:05:E | [RFC5104]                               |
   | a=sendonly 9:26:33:E8:70:88:A2               | [RFC3264]                               |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ssrc:11111 a=rtcp-rsize                      | [RFC5576] [RFC5506]                     |
   | cname:LP/NWs1ao1HmN4Xa5 a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:074c6550 a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 474af08a068 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:11111                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 1 UDP  2113667327   | [RFC5245]                     |
   | 192.168.1.4 54609 61665 typ host        |                               |
   | a=candidate:1 1 UDP  694302207    | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=candidate:0 2 UDP 2113667326   | [RFC5245]                      |
   | 192.168.1.4 64678 typ host       |                                |
   | a=candidate:1 2 UDP  1694302206  | [RFC5245]                      |
   | 24.23.204.141 64678 typ srflx 61665     |                               |
   | raddr 192.168.1.4 rport 64678 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 0 UDP/TLS/RTP/SAVPF 98    | bundle-only video line with   |
   | 100 101 103                       | port number set to zero       |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=bundle-only                     | [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | egotiation]                   |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:m1                          | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                        |
   | a=rtcp:64678 IN IP4              | [RFC3605]                      |
   | 24.23.204.141 (tb                        |
   | a=sendonly                        | a=mid:m1                         | [RFC5888] [RFC3264]                     |
   | a=rtpmap:98 VP8/90000             | [I-D.ietf-payload-vp8]        |
   | a=rtpmap:100 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=rtpmap:101 rtx/90000            | [RFC4588]                     |
   | a=rtpmap:103 rtx/90000            | [RFC4588]                     |
   | a=fmtp:98 max-fr=30;max-fs=8040   | [RFC4566]                     |
   | a=fmtp:100 max-fr=15;max-fs=1200  | [RFC4566]                     |
   | a=fmtp:101 apt=98;rtx-time=200    | [RFC4588]                     |
   | a=fmtp:103 apt=100;rtx-time=200   | [RFC4588]                     |
   | a=rid:1 send pt=98; a=setup:actpass                   | [I-D.ietf-mmusic-rid] 1:1 [RFC4145]                     |
   | a=rtcp-mux                        | mapping between the PT and the [RFC5761]                     |
   | a=rtcp-fb:* nack                  | 'rid' identifier [RFC5104]                     |
   | a=rid:2 send pt=100; a=rtcp-fb:* nack pli              | [I-D.ietf-mmusic-rid] 1:1 [RFC5104]                     |
   | a=rtcp-fb:* ccm fir               | mapping between the PT and the [RFC5104]                     |
   | a=rtcp-rsize                      | 'rid' identifier [RFC5506]                     |
   | a=simulcast: send 1;2 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-simulcast [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | ] egotiation]                   |
   | a=ssrc-group:FID 12345 34567 a=ssrc:22222                      | [RFC5888] [RFC5576] - Encoding-1 SSRC   |
   | a=ssrc-group:FID 78990 90887 cname:EocUG1f0fcg/yvY7            | [RFC5888]                               |
   | a=ssrc:12345 a=ssrc:33333                      | [RFC5576] - Encoding-1 RTX    |
   | cname:Q/NWs1ao1HmN4Xa5 cname:EocUG1f0fcg/yvY7            | SSRC                          |
   | a=ssrc:78990 a=ssrc-group:FID 22222 33333      | [RFC5576] [RFC5888]                     |
   | cname:Q/NWs1ao1HmN4Xa5 a=ssrc:44444                      | [RFC5576] - Encoding-2 SSRC   |
   | a=ssrc:34567 cname:EocUG1f0fcg/yvY7            | [RFC5576]                               |
   | cname:Q/NWs1ao1HmN4Xa5 a=ssrc:55555                      | [RFC5576] - Encoding-2 RTX    |
   | a=ssrc:90887 cname:EocUG1f0fcg/yvY7            | [RFC5576] SSRC                          |
   | cname:Q/NWs1ao1HmN4Xa5 a=ssrc-group:FID 44444 55555      | [RFC5888]                     |
   | a=sendonly a=rid:1 send pt=98;               | [RFC3264] [I-D.ietf-mmusic-rid] 1:1     |
   | a=rtcp-mux                                   | [RFC5761] mapping between the PT and    |
   | a=bundle-only                                   | [I-D.ietf-mmusic-sdp-bundle-ne the 'rid' identifier          |
   | a=rid:2 send pt=100;              | gotiation] [I-D.ietf-mmusic-rid] 1:1     |
   | a=rtcp-fb:* nack                                   | [RFC5104] mapping between the PT and    |
   | a=rtcp-fb:* nack pli                                   | [RFC5104] the 'rid' identifier          |
   | a=rtcp-fb:* ccm fir a=simulcast: send 1;2             | [RFC5104] [I-D.ietf-mmusic-sdp-simulcas |
   | a=rtcp-rsize                                   | [RFC5506] t]                            |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                Table 32: 31: 5.3.4 SDP Offer w/Simulcast, RTX

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Bob supports      |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:49203 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:m0 a=recvonly                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | a=ptime:20 [RFC5245]                     | [I-D.ietf-payload-rtp-opus]
   | 74af08a068                        |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | a=recvonly                               | [RFC3264]
   | 1:58:D0:A1:2C:19:08               |                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     | a=ice-pwd:a28a397a4c3f31747d1ee3
   | [RFC5245] hdrext:ssrc-audio-level           |                               |
   | 474af08a068 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:54321                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 2 1 UDP 2113667326    | [RFC5245]                     |
   | 192.168.1.7 60065 51556 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206   | [RFC5245]                     |
   | 98.248.92.77 60065 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 60065 51556     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   | ****** Video m=line *********     | ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | BUNDLE accepted with Bundle   |
   | 98 101                            | address identical to audio    |
   |                                   | m-line                        |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m1                          | [RFC5888]                     |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=mid:m1 a=recvonly                        | [RFC5888] [RFC3264]                     |
   | a=rtpmap:98 VP8/90000             | [I-D.ietf-payload-vp8]        |
   | a=rtpmap:101 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=fmtp:98 max-fr=30;max-fs=8040   | [RFC4566]                     |
   | a=fmtp:101 apt=98;rtx-time=200    | [RFC4588]                     |
   | a=rid:1 recv pt=98;              | [I-D.ietf-mmusic-rid]          |
   | a=simulcast: recv 1              | [I-D.ietf-mmusic-sdp-simulcast |
   |                                  | ] Bob rejects the second       |
   |                                  | simulcast stream and the       |
   | a=fingerprint:sha-256 6B:8B:F0:65 | associated rtx stream. [RFC5245]                     |
   | a=ice-ufrag:074c6550 :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B | [RFC5245]                               |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [RFC5245]                               |
   | 474af08a068 1:58:D0:A1:2C:19:08               |                               |
   | a=fingerprint:sha-1 99:41:49:83: a=setup:active                    | [RFC5245] [RFC4145]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=rtcp-mux                        | [RFC5761]                     |
   | 9d:1f:66:79:a8:07 a=rtcp-rsize                      | [RFC5506]                     |
   | a=candidate:0 2 UDP 2113667326 a=extmap:2 urn:ietf:params:rtp-   | [RFC5245] [I-D.ietf-mmusic-sdp-bundle-n |
   | 192.168.1.7 60065 typ host hdrext:sdes:mid                   | egotiation]                   |
   | a=candidate:1 2 UDP  1694302206 a=ssrc:98765                      | [RFC5245] [RFC5576]                     |
   | 98.248.92.77 60065 typ srflx cname:Q/NWs1ao1HmN4Xa5            |                               |
   | raddr 192.168.1.5 rport 60065 a=rid:1 recv pt=98;               | [I-D.ietf-mmusic-rid]         |
   | a=simulcast: recv 98 1               | [I-D.ietf-mmusic-sdp-simulcast [I-D.ietf-mmusic-sdp-simulcas |
   |                                   | ] t] Bob accepts only one rejects the second     |
   |                                   | simulcast resolution           |
   | a=ssrc:54321                     | [RFC5576]                      |
   | cname:NWs1ao1HmN4Xa5             |                                |
   | a=recvonly                       | [RFC3264]                      |
   | a=setup:active                   | [RFC4145]                      |
   | a=rtcp-mux                       | [RFC5761]                      |
   | a=bundle-only                    | [I-D.ietf-mmusic-sdp-bundle-ne |
   |                                  | gotiation] stream and the      |
   | a=rtcp-rsize                                   | [RFC5506] associated rtx stream.        |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

            Table 33: 32: 5.3.4 SDP Answer no (one Simulcast Rejected)

5.3.5.  Simulcast Video Session with Forward Error Correction

   This section shows an SDP Offer/Answer exchange for Simulcast video
   stream at two resolutions and and has [RFC5956] style FEC flows.

   On completion of the Offer/Answer exchange mechanism we end up one
   audio stream, 2 simulcast video streams and 2 associated FEC streams
   are sent over a single 5-tuple.

      Simulcast Streams with Forward Error Correction

Alice                                                            Bob
|                                                               |
|                                                               |
|                                                               |
|Alice offers single audio and simulcasted video streams        |
|with bundle-only                                               |
|                                                               |
|                                                               |
|Offer(Audio:Opus Video:VP8 with 2 resolutions with FEC Streams)|
|-------------------------------------------------------------->|
|                                                               |
|                                                               |Bob
|                                                               |accepts
|                                                               |Alice's
|                                                               |offer
|Answer(Audio:Opus Video:VP8 with 2 resolutions w/FEC Streams)  |
|<--------------------------------------------------------------|
|                                                               |
|One-Way Audio,Video session with 4 video streams(Simulcast     |
| and FEC) all multiplexed                                      |
|...............................................................|
|                                                               |
|                                                               |
|                                                               |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation] Alice supports    |
   |                                   | grouping of m=lines under     |
   |                                   | BUNDLE semantics              |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:64678 IN IP4 a=sendonly                        | [RFC3605] [RFC3264]                     |
   | 24.23.204.141 a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=mid:m0 a=maxptime:120                    | [RFC5888] [RFC4566]                     |
   | a=rtpmap:109 opus/48000/2 a=ice-ufrag:074c6550              | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=extmap:1 urn:ietf:params:rtp- a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC6464] [RFC5245]                     |
   | hdrext:ssrc-audio-level 74af08a068                        |                               |
   | a=ptime:20 a=fingerprint:sha-256 19:E2:1C:3B | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=rtcp-fb:109 nack :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | [RFC5104]                               |
   | a=sendonly :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | [RFC3264]                               |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ssrc:11111 a=rtcp-rsize                      | [RFC5576] [RFC5506]                     |
   | cname:Q/NWs1ao1HmN4Xa5 a=rtcp-fb:109 nack                | [RFC5104]                     |
   | a=ice-ufrag:074c6550 a=extmap:1 urn:ietf:params:rtp-   | [RFC5245] [RFC6464]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 474af08a068 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=fingerprint:sha-1 99:41:49:83: hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=ssrc:11111                      | [RFC5576]                     |
   | 9d:1f:66:79:a8:07 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 1 UDP  2113667327   | [RFC5245]                     |
   | 192.168.1.4 54609 61665 typ host        |                               |
   | a=candidate:1 1 UDP  694302207    | [RFC5245]                     |
   | 24.23.204.141 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 54609    |                                |
   | a=candidate:0 2 UDP 2113667326   | [RFC5245]                      |
   | 192.168.1.4 64678 typ host       |                                |
   | a=candidate:1 2 UDP  1694302206  | [RFC5245]                      |
   | 24.23.204.141 64678 typ srflx 61665     |                               |
   | raddr 192.168.1.4 rport 64678 a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] |
   | a=rtcp-rsize ****** Video m=line *********     | [RFC5506] ***************************** |
   | m=video 0 UDP/TLS/RTP/SAVPF 98    | bundle-only video line with   |
   | 100 101 103                       | port number set to zero       |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=msid:ma tb                     | Identifies RTCMediaStream ID   |
   | a=bundle-only                     | (ma) and RTCMediaStreamTrack [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | ID (tb) egotiation]                   |
   | a=rtcp:64678 a=rtcp:54609 IN IP4              | [RFC3605]                      |
   | 24.23.204.141 | [RFC3605]                     |
   | a=mid:m1                          | [RFC5888] Video m=line part of   |
   |                                   | of BUNDLE group               |
   | a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (tb)                       |
   | a=sendonly                        | [RFC3264]                     |
   | a=rtpmap:98 VP8/90000             | [I-D.ietf-payload-vp8]        |
   | a=rtpmap:100 VP8/90000            | [I-D.ietf-payload-vp8]        |
   | a=rtpmap:101 flexfec/90000        | [RFC5956] [I-D.ietf-payload-flexible-fe |
   |                                   | c-scheme]                     |
   | a=rtpmap:103 flexfec/90000        | [RFC5956] [I-D.ietf-payload-flexible-fe |
   |                                   | c-scheme]                     |
   | a=fmtp:98 max-fr=30;max-fs=8040   | [RFC4566]                     |
   | a=fmtp:100 max-fr=15;max-fs=1200  | [RFC4566]                     |
   | a=fmtp:101 L=5; D=10; ToP=2;      | [RFC5956] [I-D.ietf-payload-flexible-fe |
   | repair-window=200000              | c-scheme]                     |
   | a=fmtp:103 L=5; D=10; ToP=2;      | [RFC5956] [I-D.ietf-payload-flexible-fe |
   | repair-window=200000              | c-scheme]                     |
   | a=rid:1 send pt=98; a=setup:actpass                   | [I-D.ietf-mmusic-rid] 1:1 [RFC4145]                     |
   | a=rtcp-mux                        | mapping between the PT and the [RFC5761]                     |
   | a=rtcp-rsize                      | 'rid' identifier [RFC5506]                     |
   | a=rid:2 send pt=100; a=rtcp-fb:* nack                  | [I-D.ietf-mmusic-rid] 1:1 [RFC5104]                     |
   | a=rtcp-fb:* nack pli              | mapping between the PT and the [RFC5104]                     |
   | a=rtcp-fb:* ccm fir               | 'rid' identifier [RFC5104]                     |
   | a=simulcast: send 1;2 a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-simulcast [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | ] egotiation]                   |
   | a=ssrc:12345 a=ssrc:22222                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5 cname:EocUG1f0fcg/yvY7            |                               |
   | a=ssrc:78990 a=ssrc:33333                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5 cname:EocUG1f0fcg/yvY7            |                               |
   | a=ssrc:34567 a=ssrc-group:FEC-FR 22222 33333   | [RFC5576] [RFC5956]                     |
   | cname:Q/NWs1ao1HmN4Xa5 a=ssrc:44444                      | [RFC5576]                     |
   | a=ssrc:90887 cname:EocUG1f0fcg/yvY7            | [RFC5576]                               |
   | cname:Q/NWs1ao1HmN4Xa5 a=ssrc:55555                      | [RFC5576]                     |
   | a=ssrc-group:FEC-FR 12345 34567 cname:EocUG1f0fcg/yvY7            | [RFC5956]                               |
   | a=ssrc-group:FEC-FR 78990 90887 44444 55555   | [RFC5956]                     |
   | a=sendonly a=rid:1 send pt=98;               | [RFC3264] [I-D.ietf-mmusic-rid] 1:1     |
   | a=rtcp-mux                                   | [RFC5761] mapping between the PT and    |
   | a=bundle-only                                   | [I-D.ietf-mmusic-sdp-bundle-ne the 'rid' identifier          |
   | a=rid:2 send pt=100;              | gotiation] [I-D.ietf-mmusic-rid] 1:1     |
   | a=rtcp-fb:* nack                                   | [RFC5104] mapping between the PT and    |
   | a=rtcp-fb:* nack pli                                   | [RFC5104] the 'rid' identifier          |
   | a=rtcp-fb:* ccm fir a=simulcast: send 1;2             | [RFC5104] [I-D.ietf-mmusic-sdp-simulcas |
   | a=rtcp-rsize                                   | [RFC5506] t]                            |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 34: 33: 5.3.5 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20519 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS m0           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE m0 m1              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109                               |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=msid:ma ta                     | Identifies RTCMediaStream ID   |
   |                                  | (ma) and RTCMediaStreamTrack   |
   |                                  | ID (ta)                        |
   | a=rtcp:60065 a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m0                          | [RFC5888] Audio m=line part of   |
   |                                   | of BUNDLE group with a unique |
   |                                   | port number                   |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=recvonly                        | [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=maxptime:120                    | [RFC6464] [RFC4566]                     |
   | hdrext:ssrc-audio-level a=ice-ufrag:074c6550              | [RFC5245]                     |
   | a=ptime:20 a=ice-pwd:a28a397a4c3f31747d1ee34 | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=rtcp-fb:109 nack 74af08a068                        | [RFC5104]                               |
   | a=recvonly a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=rtcp-fb:109 nack                | [RFC5245] [RFC5104]                     |
   | a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     | 474af08a068
   | hdrext:ssrc-audio-level           |                               | a=fingerprint:sha-1 99:41:49:83:
   | [RFC5245] a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:9d
   | a=ssrc:54321                      | [RFC5576]                     |
   | : 1f:66:79:a8:07 cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 2 1 UDP 2113667326    | [RFC5245]                     |
   | 192.168.1.7 60065 51556 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206   | [RFC5245]                     |
   | 98.248.92.77 60065 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 60065 51556     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [I-D.ietf-mmusic-trickle-ice] | [RFC5506]
   | ****** Video m=line *********     | ***************************** |
   | m=video 49203 UDP/TLS/RTP/SAVPF   | BUNDLE accepted with Bundle   |
   | 98 100 101 103                    | Address identical to audio    |
   |                                   | m=line.                       |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=msid:ma tb                     | Identifies RTCMediaStream ID   |
   |                                  | (ma) and RTCMediaStreamTrack   |
   |                                  | ID (tb)                        |
   | a=rtcp:60065 a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:m1                          | [RFC5888] Video m=line part of   |
   |                                   | of BUNDLE group               |
   | a=rtpmap:98 VP8/90000            | [I-D.ietf-payload-vp8]         |
   | a=rtpmap:100 VP8/90000           | [I-D.ietf-payload-vp8]         |
   | a=rtpmap:101 flexfec/90000       | [RFC5956]                      |
   | a=rtpmap:103 flexfec/90000       | [RFC5956]                      |
   | a=fmtp:98 max-fr=30;max-fs=8040  | [RFC4566]                      |
   | a=fmtp:100 max-fr=15;max-fs=1200 | [RFC4566]                      |
   | a=fmtp:101 L=5; D=10; ToP=2;     | [RFC5956]                      |
   | repair-window=200000 a=msid:ma tb                      | Identifies RTCMediaStream ID  |
   | a=fmtp:103 L=5; D=10; ToP=2;                                   | [RFC5956] (ma) and RTCMediaStreamTrack  |
   | repair-window=200000                                   | ID (tb)                       |
   | a=rid:1 recv pt=98; a=recvonly                        | [I-D.ietf-mmusic-rid] [RFC3264]                     |
   | a=rid:2 recv pt=100; a=rtpmap:98 VP8/90000             | [I-D.ietf-mmusic-rid] [I-D.ietf-payload-vp8]        |
   | a=simulcast: recv 1;2 a=rtpmap:100 VP8/90000            | [I-D.ietf-mmusic-sdp-simulcast [I-D.ietf-payload-vp8]        |
   | a=rtpmap:101 flexfec/90000        | ] [I-D.ietf-payload-flexible-fe |
   | a=recvonly                                   | [RFC3264] c-scheme]                     |
   | a=setup:active a=rtpmap:103 flexfec/90000        | [RFC4145] [I-D.ietf-payload-flexible-fe |
   | a=rtcp-mux                                   | [RFC5761] c-scheme]                     |
   | a=bundle-only a=fmtp:98 max-fr=30;max-fs=8040   | [I-D.ietf-mmusic-sdp-bundle-ne [RFC4566]                     |
   | a=fmtp:100 max-fr=15;max-fs=1200  | gotiation] [RFC4566]                     |
   | a=ice-ufrag:074c6550 a=fmtp:101 L=5; D=10; ToP=2;      | [RFC5245] [I-D.ietf-payload-flexible-fe |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 repair-window=200000              | [RFC5245] c-scheme]                     |
   | 474af08a068 a=fmtp:103 L=5; D=10; ToP=2;      | [I-D.ietf-payload-flexible-fe |
   | a=fingerprint:sha-1 99:41:49:83: repair-window=200000              | [RFC5245] c-scheme]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | 9d:1f:66:79:a8:07 :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | a=candidate:0 2 UDP 2113667326 :35 :DC:B8:5F:64:1A:24:C2:43:F0:A | [RFC5245]                               |
   | 192.168.1.7 60065 typ host 1:58:D0:A1:2C:19:08               |                               |
   | a=candidate:1 2 UDP  1694302206 a=setup:active                    | [RFC5245] [RFC4145]                     |
   | 98.248.92.77 60065 typ srflx a=rtcp-mux                        | [RFC5761]                     |
   | raddr 192.168.1.7 rport 60065 a=rtcp-rsize                      | [RFC5506]                     |
   | a=rtcp-fb:* nack                  | [RFC5104]                     |
   | a=rtcp-fb:* nack pli              | [RFC5104]                     |
   | a=rtcp-fb:* ccm fir               | [RFC5104]                     |
   | a=rtcp-rsize a=extmap:2 urn:ietf:params:rtp-   | [RFC5506] [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | a=ssrc:98765                      |
   +----------------------------------+--------------------------------+ [RFC5576]                     |
   | cname:EocUG1f0fcg/yvY7            |                               |
   | a=rid:1 recv pt=98;               | [I-D.ietf-mmusic-rid]         |
   | a=rid:2 recv pt=100;              | [I-D.ietf-mmusic-rid]         |
   | a=simulcast: recv 1;2             | [I-D.ietf-mmusic-sdp-simulcas |
   |                                   | t]                            |
   +-----------------------------------+-------------------------------+

                        Table 35: 34: 5.3.5 SDP Answer

5.4.  Others

   The examples in the section provide SDP Offer/Answer exchange for a
   variety of scenarios related to RTP Header extension, extension for conference
   usages, Legacy Interop scenarios and more.

5.4.1.  Audio Session - Voice Activity Detection

   This example shows Alice indicating the support of the RTP header
   extension to include the audio-level of the audio sample carried in
   the RTP packet.

              2-Way Audio with VAD

    Alice                                    Bob
    |                                         |
    |                                         |
    |Alice indicates support for including    |
    |audio level in RTP header                |
    |                                         |
    |     Offer(Audio:Opus,PCMU,PCMA)         |
    |---------------------------------------->|
    |                                         |
    |                                         |
    |     Answer(Audio:Opus,PCMU,PCMA)        |
    |<----------------------------------------|
    |                                         |
    |                                         |Bob accepts and
    |                                         |indicates his
    |                                         |support as well
    |                                         |
    |     Two way Opus Audio                  |
    |.........................................|
    |                                         |
    |Per packet audio-level is included in the|
    |RTP header                               |
    |                                         |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566]                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 8                           |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:64678 IN IP4 a=sendrecv                        | [RFC3605] [RFC3264]                     |
   | 24.23.204.141 a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=extmap:1 urn:ietf:params:rtp- a=rtpmap:0 PCMU/8000              | [RFC6464] [RFC3551]                     |
   | hdrext:ssrc-audio-level a=rtpmap:8 PCMA/8000              | [RFC3551]                     |
   | a=rtpmap:109 opus/48000/2 a=maxptime:120                    | [I-D.ietf-payload-rtp-opus] [RFC4566]                     |
   | a=ptime:20 a=ice-ufrag:074c6550              | [I-D.ietf-payload-rtp-opus] [RFC5245]                     |
   | a=rtpmap:0 PCMU/8000 a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC3551] [RFC5245]                     |
   | a=rtpmap:0 PCMA/8000 74af08a068                        | [RFC3551]                               |
   | a=sendrecv a=fingerprint:sha-256 19:E2:1C:3B | [RFC3264] [RFC5245]                     |
   | a=setup:actpass :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 | [RFC4145]                               |
   | a=rtcp-mux :04 :BB:05:2F:70:9F:04:A9:0E:05:E | [RFC5761]                               |
   | a=ice-ufrag:074c6550 9:26:33:E8:70:88:A2               | [RFC5245]                               |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=setup:actpass                   | [RFC5245] [RFC4145]                     |
   | 474af08a068 a=rtcp-mux                        | [RFC5761]                     |
   | a=fingerprint:sha-1 99:41:49:83: a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7: a=rtcp-fb:* nack                  | [RFC5104]                     |
   | 70:9d:1f:66:79:a8:07 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=candidate:0 1 UDP  2113667327 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 192.168.1.4 54609 typ host a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=candidate:1 1 UDP  694302207 hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 24.23.204.141 54609 typ srflx a=ssrc:12345                      | [RFC5576]                     |
   | raddr 192.168.1.4 rport 54609 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326  2113667327   | [RFC5245]                     |
   | 192.168.1.4 64678 61665 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206  694302207    | [RFC5245]                     |
   | 24.23.204.141 64678 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 64678    |                                |
   | a=rtcp-fb:* nack                 | [RFC5104]                      |
   | a=ssrc:11111                     | [RFC5576]                      |
   | cname:QCL/1HmN4Xa5CClapa 61665     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 36: 35: 5.4.1 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin     |
   |                                  | Information                     |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 98                          |                               |
   | c=IN c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC4566] [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=extmap:1 urn:ietf:params:rtp- a=sendrecv                        | [RFC6464] [RFC3264] - Bob can send and  |
   | hdrext:ssrc-audio-level                                   | recv audio                    |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus] - |
   |                                   | Bob accepts only Opus Codec   |
   | a=ptime:20                       | [I-D.ietf-payload-rtp-opus]    |
   | a=rtpmap:0 PCMU/8000              | [RFC3551] PCMU Audio Codec    |
   | a=rtpmap:0 PCMA/8000              | [RFC3551] PCMA Audio Codec    |
   | a=rtcp-fb:* nack a=maxptime:120                    | [RFC5104] [RFC4566]                     |
   | a=sendrecv a=ice-ufrag:c300d85b              | [RFC3264] - Bob can send and [RFC5245]                     |
   | a=ice-pwd:de4e99bd291c325921d5d47 | [RFC5245]                     |
   | efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | recv audio                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761] - Bob can perform   |
   |                                   | RTP/RTCP Muxing on port 49203 |
   | a=ice-ufrag:c300d85b a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 a=rtcp-fb:* nack                  | [RFC5245] [RFC5104]                     |
   | 7efbabd9a2 a=extmap:1 urn:ietf:params:rtp-   | [RFC6464]                     |
   | hdrext:ssrc-audio-level           | a=fingerprint:sha-1 99:41:49:83:                               | [RFC5245]
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n | 4a:97:0e:1f:ef:6d:f7:c9:c7:70:
   | hdrext:sdes:mid                   | egotiation]                   | 9d:1f:66:79:a8:07
   | a=ssrc:54321                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 49203 51556 typ host        |                               |
   | a=candidate:1 1 UDP 1694302207    | [RFC5245]                     |
   | 98.248.92.77 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 49203    |                                |
   | a=ssrc:1732846380                | [RFC5576]                      |
   | cname:EocUG1f0fcg/yvY7 51556     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                        Table 37: 36: 5.4.1 SDP Answer

5.4.2.  Audio Conference - Voice Activity Detection

   This example shows SDP for RTP header extension that allows RTP-level
   mixers in audio conferences to deliver information about the audio
   level of individual participants.

        Audio Conference with VAD Support

   Alice                                    Mixer
   |                                         |
   |Alice indicates her interest to audio    |
   |levels for the contributing sources      |
   |                                         |
   |Offer(Audio:Opus,PCMU,PCMA)              |
   |---------------------------------------->|
   |                                         |
   |                                         |
   |Answer(Audio:Opus,PCMU,PCMA)             |
   |<----------------------------------------|
   |                                         |
   |                                         |Mixer indicates
   |                                         |it can provide
   |                                         |audio-levels
   |Two way Opus Audio                       |
   |.........................................|
   |                                         |
   |Audio-levels per CSRCS is included in the|
   |RTP header                               |
   |                                         |

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Offer SDP Contents                | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=- 20518 0 IN IP4 0.0.0.0        | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 54609 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 8                           |                               |
   | c=IN IP4 24.23.204.141            | [RFC4566]                     |
   | a=rtcp:54609 IN IP4 24.23.204.141 | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:64678 IN IP4              | [RFC3605]                      |
   | 24.23.204.141                    |                                |
   | a=extmap:1/recvonly              | [RFC6465]                      |
   | urn:ietf:params:rtp-hdrext:csrc- |                                |
   | audio-level                      |                                |
   | a=extmap:1 urn:ietf:params:rtp- a=sendrecv                        | [RFC6464] [RFC3264] - Alice can send    |
   | hdrext:ssrc-audio-level                                   | and recv audio                |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=ptime:20                       | [I-D.ietf-payload-rtp-opus]    |
   | a=rtpmap:0 PCMU/8000              | [RFC3551] PCMU Audio Codec    |
   | a=rtpmap:0 PCMA/8000              | [RFC3551] PCMA Audio Codec    |
   | a=rtcp-fb:* nack a=maxptime:120                    | [RFC5104] [RFC4566]                     |
   | a=sendrecv a=ice-ufrag:074c6550              | [RFC3264] - Alice can send and [RFC5245]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee34 | [RFC5245]                     |
   | 74af08a068                        |                               |
   | a=fingerprint:sha-256 19:E2:1C:3B | [RFC5245]                     |
   | :4B:9F:81:E6:B8:5C:F4:A5:A8:D8:73 |                               |
   | :04 :BB:05:2F:70:9F:04:A9:0E:05:E |                               |
   | 9:26:33:E8:70:88:A2               | recv audio                               |
   | a=setup:actpass                   | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:a28a397a4c3f31747d1ee3 a=rtcp-fb:* nack                  | [RFC5245] [RFC5104]                     |
   | 474af08a068 a=extmap:1/recvonly               | [RFC6465]                     |
   | a=fingerprint:sha-1 99:41:49:83: urn:ietf:params:rtp-hdrext:csrc-  | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7:70: audio-level                       |                               |
   | 9d:1f:66:79:a8:07 a=extmap:2 urn:ietf:params:rtp-   | [RFC6464]                     |
   | a=candidate:0 1 UDP  2113667327 hdrext:ssrc-audio-level           | [RFC5245]                               |
   | 192.168.1.4 54609 typ host a=extmap:3 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | a=candidate:1 1 UDP  694302207 hdrext:sdes:mid                   | [RFC5245] egotiation]                   |
   | 24.23.204.141 54609 typ srflx a=ssrc:12345                      | [RFC5576]                     |
   | raddr 192.168.1.4 rport 54609 cname:EocUG1f0fcg/yvY7            |                               |
   | a=candidate:0 2 1 UDP 2113667326  2113667327   | [RFC5245]                     |
   | 192.168.1.4 64678 61665 typ host        |                               |
   | a=candidate:1 2 1 UDP  1694302206  694302207    | [RFC5245]                     |
   | 24.23.204.141 64678 54609 typ srflx     |                               |
   | raddr 192.168.1.4 rport 64678    |                                |
   | a=ssrc:11111                     | [RFC5576]                      |
   | cname:QCL/1HmN4Xa5CClapa 61665     |                               |
   | a=rtcp-rsize a=end-of-candidates               | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                         Table 38: 37: 5.4.2 SDP Offer

   +----------------------------------+--------------------------------+

   +-----------------------------------+-------------------------------+
   | Answer SDP Contents               | RFC#/Notes                    |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+
   | v=0                               | [RFC4566]                     |
   | o=-  16833 0 IN IP4 0.0.0.0       | [RFC4566] - Session Origin    |
   |                                   | Information                   |
   | s=-                               | [RFC4566]                     |
   | t=0 0                             | [RFC4566]                     |
   | a=msid-semantic:WMS ma           | [I-D.ietf-mmusic-msid]         |
   | a=group:BUNDLE audio              | [I-D.ietf-mmusic-sdp-bundle-ne [I-D.ietf-mmusic-sdp-bundle-n |
   |                                   | gotiation] egotiation]                   |
   | a=ice-options:trickle             | [I-D.ietf-mmusic-trickle-ice] |
   | ****** Audio m=line *********     | ***************************** |
   | m=audio 49203 UDP/TLS/RTP/SAVPF   | [RFC4566]                     |
   | 109 0 98                          |                               |
   | c=IN IP4 98.248.92.77             | [RFC4566]                     |
   | a=rtcp:49203 IN IP4 98.248.92.77  | [RFC3605]                     |
   | a=mid:audio                       | [RFC5888]                     |
   | a=msid:ma ta                      | Identifies RTCMediaStream ID  |
   |                                   | (ma) and RTCMediaStreamTrack  |
   |                                   | ID (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77 | [RFC3605]                      |
   | a=extmap:1/sendonly              | [RFC6465]                      |
   | urn:ietf:params:rtp-hdrext:csrc- |                                |
   | audio-level a=sendrecv                        | [RFC3264]                     |
   | a=rtpmap:109 opus/48000/2         | [I-D.ietf-payload-rtp-opus]   |
   | a=ptime:20                       | [I-D.ietf-payload-rtp-opus]    |
   | a=rtpmap:0 PCMU/8000              | [RFC3551] PCMU Audio Codec    |
   | a=rtpmap:0 PCMA/8000              | [RFC3551] PCMA Audio Codec    |
   | a=rtcp-fb:* nack a=maxptime:120                    | [RFC5104] [RFC4566]                     |
   | a=sendrecv a=ice-ufrag:c300d85b              | [RFC5245]                     |
   | a=ice-pwd:de4e99bd291c325921d5d47 | [RFC5245]                     |
   | efbabd9a2                         |                               |
   | a=fingerprint:sha-256 6B:8B:F0:65 | [RFC5245]                     |
   | :5F:78:E2:51:3B:AC:6F:F3:3F:46:1B |                               |
   | :35 :DC:B8:5F:64:1A:24:C2:43:F0:A |                               |
   | 1:58:D0:A1:2C:19:08               | [RFC3264]                               |
   | a=setup:active                    | [RFC4145]                     |
   | a=rtcp-mux                        | [RFC5761]                     |
   | a=ice-ufrag:c300d85b a=rtcp-rsize                      | [RFC5245] [RFC5506]                     |
   | a=ice-pwd:de4e99bd291c325921d5d4 a=rtcp-fb:* nack                  | [RFC5245] [RFC5104]                     |
   | 7efbabd9a2 a=extmap:1/sendonly               | [RFC6465]                     |
   | a=fingerprint:sha-1 99:41:49:83: urn:ietf:params:rtp-hdrext:csrc-  | [RFC5245]                               |
   | 4a:97:0e:1f:ef:6d:f7:c9:c7: audio-level                       |                               |
   | a=extmap:2 urn:ietf:params:rtp-   | [I-D.ietf-mmusic-sdp-bundle-n |
   | hdrext:sdes:mid                   | egotiation]                   |
   | 70:9d:1f:66:79:a8:07 a=ssrc:54321                      | [RFC5576]                     |
   | cname:Q/NWs1ao1HmN4Xa5            |                               |
   | a=candidate:0 1 UDP 2113667327    | [RFC5245]                     |
   | 192.168.1.7 49203 51556 typ host        |                               |
   | a=candidate:1 1 UDP 1694302207    | [RFC5245]                     |
   | 98.248.92.77 49203 typ srflx      |                               |
   | raddr 192.168.1.7 rport 49203 51556     |                               |
   | a=ssrc:2222 cname:HmN4Xa5CC/lapa a=end-of-candidates               | [RFC5576]                      |
   | a=rtcp-rsize                     | [RFC5506] [I-D.ietf-mmusic-trickle-ice] |
   +----------------------------------+--------------------------------+
   +-----------------------------------+-------------------------------+

                        Table 39: 38: 5.4.2 SDP Answer

5.4.3.  Successful legacy Interop Fallback with bundle-only

   In the scenario described below, Alice is a multi-stream capable
   WebRTC endpoint while Bob is a legacy VOIP end-point.  The SDP Offer/
   Answer exchange demonstrates successful session setup with fallback
   to audio only stream negotiated via bundle-only framework between the
   end-points.  Specifically,
   o  Offer from Alice describes 2 cameras via 2 video m=lines with both
      marked as bundle-only.

   o  Since Bob doesnot recognize either the BUNDLE mechanism or the
      bundle-only attribute, he accepts only the audio stream from
      Alice.

   NOTE: Since Alice is unaware of Bob's support for BUNDLE framework,
   Alice ensures to include separate RTP/RTCP ports and candidate
   information.

         Successful 2-Way WebRTC <-> VOIP Interop

Alice                                                       Bob
|                                                           |
|                                                           |
|       Alice is a multistream capable WebRTC end-point     |
|          & Bob is behind a legacy VOIP system             |
|                                                           |
|Offer(Audio:Opus Video:2 VP8,2 H2.64 Streams) with         |
|          bundle-only                                      |
|---------------------------------------------------------->|
|     Alice marks both the video streams as bundle-only     |
|                                                           |
|                                                           |
|                  Answer(Audio:Opus)                       |
|<----------------------------------------------------------|
|                                                           |Bob
|                                                           |accepts
|                                                           |audio
|                                                           |stream,
|                                                           |since he
|                                                           |doesn't
|                                                           |recognize
|                                                           |bundle-only
|                                                           |
|                   Two way Opus Audio                      |
|...........................................................|
|                                                           |
|                                                           |

   +-------------------------------------+-----------------------------+
   | Offer SDP Contents                  | RFC#/Notes                  |
   +-------------------------------------+-----------------------------+
   | v=0                                 | [RFC4566]                   |
   | o=- 20519 0 IN IP4 0.0.0.0          | [RFC4566]                   |
   | s=-                                 | [RFC4566]                   |
   | t=0 0                               | [RFC4566]                   |
   | a=msid-semantic:WMS ma              | [I-D.ietf-mmusic-msid]      |
   | a=group:BUNDLE m0 m1 m2             | [I-D.ietf-mmusic-sdp-bundle |
   |                                     | -negotiation] Alice         |
   |                                     | supports grouping of        |
   |                                     | m=lines under BUNDLE        |
   |                                     | semantics                   |
   | a=ice-options:trickle               | [I-D.ietf-mmusic-trickle-ic |
   |                                     | e]                          |
   | ****** Audio m=line *********       | *************************** |
   |                                     | **                          |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109 | [RFC4566]                   |
   | c=IN IP4 24.23.204.141              | [RFC4566]                   |
   | a=rtcp:64678 IN IP4 24.23.204.141   | [RFC3605]                   |
   | a=mid:m0                            | [RFC5888] Audio m=line part |
   |                                     | of BUNDLE group with a      |
   |                                     | unique port number          |
   | a=msid:ma ta                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (ta) |
   | a=sendrecv                          | [RFC3264]                   |
   | a=rtpmap:109 opus/48000/2           | [I-D.ietf-payload-rtp-opus] |
   | a=extmap:1 urn:ietf:params:rtp- a=rtcp-fb:109 nack                  | [RFC6464] [RFC5104]                   |
   | hdrext:ssrc-audio-level a=maxptime:120                      | [RFC4566]                   |
   | a=ptime:20 a=ice-ufrag:074c6550                | [I-D.ietf-payload-rtp-opus] [RFC5245]                   |
   | a=rtcp-fb:109 nack a=ice-pwd:a28a397a4c3f31747d1ee3474 | [RFC5104] [RFC5245]                   |
   | a=sendrecv af08a068                            |                             |
   | a=fingerprint:sha-256 19:E2:1C:3B:4 | [RFC5245]                   |
   | B:9F:81:E6:B8:5C:F4:A5:A8:D8:73:04  |                             |
   | :BB:05:2F:70:9F:04:A9:0E:05:E9:26:3 |                             |
   | 3:E8:70:88:A2                       | [RFC3264]                             |
   | a=setup:actpass                     | [RFC4145]                   |
   | a=rtcp-mux                          | [RFC5761]                   |
   | a=ice-ufrag:074c6550 a=rtcp-rsize                        | [RFC5245] [RFC5506]                   |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474 a=extmap:1 urn:ietf:params:rtp-     | [RFC5245] [RFC6464]                   |
   | af08a068 hdrext:ssrc-audio-level             |                             |
   | a=fingerprint:sha-1 99:41:49:83:4a: a=extmap:2 urn:ietf:params:rtp-     | [RFC5245] [I-D.ietf-mmusic-sdp-bundle |
   | 97:0e:1f:ef:6d:f7:c9:c7:70: hdrext:sdes:mid                     | -negotiation]               |
   | 9d:1f:66:79:a8:07 a=ssrc:12345 cname:EocUG1f0fcg/yvY7 | [RFC5576]E                  |
   | a=candidate:0 1 UDP  2113667327     | [RFC5245]                   |
   | 192.168.1.4 54609 61665 typ host          |                             |
   | a=candidate:1 1 UDP  694302207      | [RFC5245]                   |
   | 24.23.204.141 54609 typ srflx raddr |                             |
   | 192.168.1.4 rport 54609 61665             |                             |
   | a=candidate:0 2 1 UDP 2113667326      | [RFC5245]                   |
   | 192.168.1.4 64678 61667 typ host          |                             |
   | a=candidate:1 2 1 UDP  1694302206     | [RFC5245]                   |
   | 24.23.204.141 64678 typ srflx raddr |                             |
   | 192.168.1.4 rport 64678             | 61667             |                             | a=ssrc:11111                        | [RFC5576]E                  |
   | cname:axzo1278npDlAzM73 ****** Video-1 m=line *********     | *************************** |
   | a=rtcp-rsize                                     | [RFC5506] **                          |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100  | bundle-only video line with |
   |                                     | port number set to zero     |
   | c=IN IP4 24.23.204.141              | [RFC4566]                   |
   | a=rtcp:64678 IN IP4 24.23.204.141 a=bundle-only                       | [I-D.ietf-mmusic-sdp-bundle |
   | [RFC3605]                                     | -negotiation]               |
   | a=mid:m1                            | [RFC5888] Video m=line part |
   |                                     | of BUNDLE group             |
   | a=msid:ma tb                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (tb) |
   | a=sendrecv                          | [RFC3264]                   |
   | a=rtpmap:98 VP8/90000               | [I-D.ietf-payload-vp8]      |
   | a=imageattr:98 [x=1280,y=720]       | [RFC6236]                   |
   | a=fmtp:98 max-fr=30                 | [RFC4566]                   |
   | a=ssrc:12345 a=setup:actpass                     | [RFC4145]                   |
   | a=rtcp-mux                          | [RFC5761]                   |
   | a=rtcp-rsize                        | [RFC5506]                   |
   | a=rtcp-fb:* nack                    | [RFC5104]                   |
   | a=rtcp-fb:* nack pli                | [RFC5576] [RFC5104]                   |
   | cname:axzo1278npDlAzM73 a=rtcp-fb:* ccm fir                 | [RFC5104]                   |
   | a=bundle-only a=extmap:2 urn:ietf:params:rtp-     | [I-D.ietf-mmusic-sdp-bundle |
   | hdrext:sdes:mid                     | -negotiation]               |
   | a=sendrecv a=ssrc:56789 cname:EocUG1f0fcg/yvY7 | [RFC3264] [RFC5576]                   |
   | a=rtcp-rsize ****** Video-2 m=line *********     | [RFC5506] *************************** |
   |                                     | **                          |
   | m=video 0 UDP/TLS/RTP/SAVPF 101 103 | bundle-only video line with |
   |                                     | port number set to zero     |
   | c=IN IP4 24.23.204.141              | [RFC4566]                   |
   | a=rtcp:64678 IN IP4 24.23.204.141 a=bundle-only                       | [I-D.ietf-mmusic-sdp-bundle |
   | [RFC3605]                                     | -negotiation]               |
   | a=mid:m2                            | [RFC5888] Video m=line part |
   |                                     | of BUNDLE group             |
   | a=msid:ma tc                        | Identifies RTCMediaStream   |
   |                                     | ID (ma) and                 |
   |                                     | RTCMediaStreamTrack ID (tc) |
   | a=sendrecv                          | [RFC3264]                   |
   | a=rtpmap:101 H264/90000             | [RFC3984]                   |
   | a=rtpmap:103 H264/90000             | [RFC3984]                   |
   | a=fmtp:101 profile-level-id=4d0028  | [RFC3984]Camera-2,Encoding- |
   | ;packetization-mode=1;max-fr=30     | 1 Resolution                |
   | a=ssrc:67890 a=rtcp-mux                          | [RFC5761]                   | [RFC5576]
   | a=rtcp-rsize                        | [RFC5506]                   | cname:axzo1278npDlAzM73
   | a=rtcp-fb:* nack                    | [RFC5104]                   | a=bundle-only
   | [I-D.ietf-mmusic-sdp-bundle a=rtcp-fb:* nack pli                | [RFC5104]                   |
   | -negotiation] a=rtcp-fb:* ccm fir                 | [RFC5104]                   | a=sendrecv
   | [RFC3264] a=extmap:2 urn:ietf:params:rtp-     | [I-D.ietf-mmusic-sdp-bundle | a=rtcp-rsize
   | [RFC5506] hdrext:sdes:mid                     | -negotiation]               |
   | a=ssrc:67890 cname:EocUG1f0fcg/yvY7 | [RFC5576]                   |
   +-------------------------------------+-----------------------------+

                 Table 40: 39: 5.4.3 SDP Simulcast bundle-only

   +------------------------------------------+------------------------+

   +----------------------------------------+--------------------------+
   | Answer SDP Contents                    | RFC#/Notes               |
   +------------------------------------------+------------------------+
   +----------------------------------------+--------------------------+
   | v=0                                    | [RFC4566]                |
   | o=- 20519 0 IN IP4 0.0.0.0             | [RFC4566]                |
   | s=-                                    | [RFC4566]                |
   | t=0 0                                  | [RFC4566]                |
   | ****** Audio m=line *********          | ************************ |
   |                                        | *****                    |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109    | [RFC4566]                |
   | c=IN IP4 24.23.204.141                 | [RFC4566]                |
   | a=rtcp:60065 IN IP4 24.23.204.141      | [RFC3605]                |
   | a=sendrecv                             | [RFC3264]                |
   | a=rtpmap:109 opus/48000/2              | [I-D.ietf-payload-rtp- [I-D.ietf-payload-rtp-op |
   |                                        | opus] us]                      |
   | a=extmap:1 urn:ietf:params:rtp-hdrext a=maxptime:120                         | [RFC6464] [RFC4566]                |
   | :ssrc-audio-level a=ice-ufrag:ufrag:c300d85b             | [RFC5245]                |
   | a=ptime:20 a=ice-                                 | [I-D.ietf-payload-rtp- [RFC5245]                |
   | pwd:de4e99bd291c325921d5d47efbabd9a2   | opus]                          |
   | a=rtcp-fb:109 nack a=fingerprint:sha-256 6B:8B:F0:65:5F:7 | [RFC5104] [RFC5245]                |
   | a=sendrecv 8:E2:51:3B:AC:6F:F3:3F:46:1B:35 :DC:B8 | [RFC3264]                          |
   | a=setup:active :5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:1 | [RFC4145]                          |
   | a=ice-ufrag:ufrag:c300d85b 9:08                                   | [RFC5245]                          |
   | a=ice- a=setup:active                         | [RFC5245] [RFC4145]                |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 a=rtcp-rsize                           | [RFC5506]                |
   | a=rtcp-fb:109 nack                     | a=fingerprint:sha-1 [RFC5104]                | [RFC5245]
   | a=extmap:1 urn:ietf:params:rtp-hdrext  | [RFC6464]                | 99:41:49:83:4a:97:0e:1f:ef:6d:f7:c9:c7:
   | :ssrc-audio-level                      |                          |
   | 70:9d:1f:66:79:a8:07 a=ssrc:54321 cname:Q/NWs1ao1HmN4Xa5    | [RFC5576]                |
   | a=candidate:0 1 UDP  2113667327        | [RFC5245]                |
   | 192.168.1.7 49203 51556 typ host             |                          |
   | a=candidate:1 1 UDP  694302207         | [RFC5245]                |
   | 98.248.92.77 49203 typ srflx raddr     |                          |
   | 192.168.1.7 rport 49203 51556                |                          |
   | a=candidate:0 2 UDP 2113667326         | [RFC5245]                |
   | 192.168.1.7 60065 51558 typ host             |                          |
   | a=candidate:1 2 UDP  1694302206        | [RFC5245]                |
   | 98.248.92.77 60065 typ srflx raddr     |                          |
   | 192.168.1.7 rport 60065 51558                |                          |
   | a=rtcp-rsize ****** Video m=line *********          | [RFC5506] ************************ |
   |                                        | *****                    |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100     | Bob doesn't recognize    |
   |                                        | bundle-only and hence    |
   |                                        | rejects the video      |
   |                                          | stream                 |
   | c=IN IP4 98.248.92.77                    | [RFC4566]              |
   | a=rtpmap:98 VP8/90000                    | [I-D.ietf-payload-vp8] m=line is rejected   |
   | a=rtpmap:100 VP8/90000                                        | [I-D.ietf-payload-vp8] implicitly due to port 0 |
   | a=imageattr:98 [x=1280,y=720] ****** Video m=line *********          | [RFC6236] ************************ |
   | a=fmtp:98 max-fr=30                                        | [RFC4566] *****                    |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100     | Bob doesn't recognize    |
   |                                        | bundle-only and hence    |
   |                                        | rejects the video      |
   |                                          | stream                 |
   | c=IN IP4 98.248.92.77                    | [RFC4566]              |
   | a=rtpmap:101 H264/90000                  | [RFC3984]              |
   | a=fmtp:101 profile-level-id=4d0028       | [RFC3984]Camera-2,Enco m=line is rejected   |
   | ;packetization-mode=1;max-fr=30                                        | ding-1 Resolution implicitly due to port 0 |
   +------------------------------------------+------------------------+
   +----------------------------------------+--------------------------+

                        Table 41: 40: 5.4.3 SDP Answer

5.4.4.  Legacy Interop with RTP/AVP profile

   In this section, we attempt to provide session descriptions
   showcasing inter-operability between a WebRTC end-point and a Legacy
   VOIP end-point.  The ideas included in here are not fully baked into
   the standards and might be controversial in nature.  The hope here is
   to demonstrate a plausible SDP composition to enchance seamless
   inter-operability between the aforementioned communication systems.

   In the scenario desribed below, Alice is a legacy end-point which
   sends [RFC3264] Offer with two sets of media descriptions per media
   type.

      One set that correponds to [WebRTC] compliant UDP/TLS/RTP/SAVPF
      based audio and video descriptions.

      Another set with RTP/AVP based audio and video descriptions for
      the legacy Interop purposes.

      Also to note, Alice includes session level DTLS information and
      media level RTCP feedback information as applicable to both the
      sets of media descriptions

   On the other hand, Bob being a WebRTC end-point, recognizes accepts
   the media descriptions with RTP/AVP profile.  The security and
   feedback requirements for the session are either handled by a
   intermediate gateway or with some combination of Alice's capabilities
   and the intermediate gateway.

           Successful 2-Way WebRTC <-> VOIP Interop

Alice                                                          Bob
|                                                               |
|                                                               |
|  Alice is a legacy VOIP End-point & Bob is a WebRTC End-Point |
|                                                               |
|                                                               |
|                                                               |
|              Offer(Audio:Opus Video:H.264)                    |
|-------------------------------------------------------------->|
|                                                               |
|                                                               |
|Alice includes 2 copies of media descriptions                  |
|1. WebRTC compliant media description (UDP/TLS/RTP/SAVPF)      |
|2. Legacy compliant media description (RTP/AVP)                |
|                                                               |
|                                                               |
|             Answer(Audio:Opus, Video:H.264)                   |
|<--------------------------------------------------------------|
|                                                               |Bob
|                                                               |accepts
|                                                               |"legacy
|                                                               |compliant"
|                                                               |m=line
|                                                               |
|                                                               |
|             Two way Opus Audio, H.264 Video                   |
|...............................................................|
|       Session also suports RTP/RTCP Mux, RTCP Feedback        |
|                                                               |

   +-----------------------------------------------+-------------------+

   +----------------------------------------+--------------------------+
   | Offer SDP Contents                     | RFC#/Notes               |
   +-----------------------------------------------+-------------------+
   +----------------------------------------+--------------------------+
   | v=0                                    | [RFC4566]                |
   | o=- 20518 0 IN IP4 0.0.0.0             | [RFC4566]                |
   | s=-                                    | [RFC4566]                |
   | t=0 0                                  | [RFC4566]                |
   | a=ice-ufrag:074c6550                   | [RFC5245]                |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474af08a068 a=ice-                                 | [RFC5245]                |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f:e pwd:a28a397a4c3f31747d1ee3474af08a068  |                          |
   | a=fingerprint:sha-256 6B:8B:F0:65:5F:7 | [RFC5245]                |
   | f:6d:f7:c9:c7:70:9d:1f:66:79:a8:07 8:E2:51:3B:AC:6F:F3:3F:46:1B:35 :DC:B8 |                          |
   | :5F:64:1A:24:C2:43:F0:A1:58:D0:A1:2C:1 |                          |
   | 9:08                                   |                          |
   | a=rtcp-rsize                           | [RFC5506]                |
   | ****** Audio m=line *********          | ************************ |
   |                                        | *****                    |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109    | [RFC4566]                |
   | c=IN IP4 24.23.204.141                 | [RFC4566]                |
   | a=rtpmap:109 opus/48000                |                          |
   | a=ptime:20                             |                          |
   | a=sendrecv                             | [RFC3264]                |
   | a=rtcp-mux                             | [RFC5761]                |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4        | [RFC5245]                |
   | 192.168.1.4 54609 typ host             |                          |
   | a=candidate:1 1 UDP  694302207 24.23.204.141         | [RFC5245]                |
   | 24.23.204.141 54609 typ srflx raddr    |                          |
   | 192.168.1.4 rport 54609                |                          |
   | a=candidate:0 2 UDP 2113667326 192.168.1.4         | [RFC5245]                |
   | 192.168.1.4 64678 typ host             |                          |
   | a=candidate:1 2 UDP  1694302206 24.23.204.141        | [RFC5245]                |
   | 24.23.204.141 64678 typ srflx raddr    |                          |
   | 192.168.1.4 rport 64678                |                          |
   | a=rtcp-fb:109 nack                     | [RFC5104]                |
   | ****** Audio m=line *********          | ************************ |
   |                                        | *****                    |
   | m=video  62537 UDP/TLS/RTP/SAVPF 120   | [RFC4566]                |
   | c=IN IP4 24.23.204.141                 | [RFC4566]                |
   | a=rtpmap:120 VP8/90000                 | [I-D.ietf-payload |
   |                                               | -vp8] [I-D.ietf-payload-vp8]   |
   | a=sendrecv                             | [RFC3264]                |
   | a=rtcp-mux                             | [RFC5761]                |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4        | [RFC5245]                |
   | 192.168.1.4 62537 typ host             |                          |
   | a=candidate:1 1 UDP  1694302207 24.23.204.141        | [RFC5245]                |
   | 24.23.204.141 62537 typ srflx raddr    |                          |
   | 192.168.1.4 rport 62537                |                          |
   | a=candidate:0 2 2113667326 192.168.1.4 54721 | [RFC5245]                |
   | 54721 typ host                         |                          |
   | a=candidate:1 2 UDP 1694302206 24.23.204.141         | [RFC5245]                |
   | 24.23.204.141 54721 typ srflx raddr    |                          |
   | 192.168.1.4 rport 54721                |                          |
   | a=rtcp-fb:120 nack pli                 | [RFC5104]                |
   | a=rtcp-fb:120 ccm fir                  | [RFC5104]                |
   | ---------------                        | These set of      |
   |                                               | media       |
   |                                        | descriptions are for     |
   |                                        | for Legacy Inter- Inter-op purposes |
   | ****** Audio m=line *********          | ************************ |
   | op purposes                                        | *****                    |
   | m=audio 54732 RTP/AVP 109              | [RFC4566]Alice    |
   |                                               | includes RTP/AVP  |
   |                                        | RTP/AVP audio stream     |
   |                                        | description              |
   | c=IN IP4 24.23.204.141                 | [RFC4566]                |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f:7 a=fingerprint:sha-256 19:E2:1C:3B:4B:9 | [RFC5245]                |
   | f:7d:f9:c9:c7:70:9d:1f:66:79:a8:07 F:81:E6:B8:5C:F4:A5:A8:D8:73:04 :BB:05 |                          |
   | :2F:70:9F:04:A9:0E:05:E9:26:33:E8:70:8 |                          |
   | 8:A2                                   |                          |
   | a=rtpmap:109 opus/48000                |                          |
   | a=ptime:20                             |                          |
   | a=sendrecv                             | [RFC3264]                |
   | a=rtcp-mux                             | [RFC5761]Alice    |
   |                                               | still includes     |
   |                                        | includes RTP/RTCP Mux    |
   |                                        | support                  |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4        | [RFC5245]                |
   | 192.168.1.4 54732 typ host             |                          |
   | a=candidate:1 1 UDP  694302207 24.23.204.141         | [RFC5245]                |
   | 24.23.204.141 54732 typ srflx raddr    |                          |
   | 192.168.1.4 rport 54732                |                          |
   | a=candidate:0 2 UDP 2113667326 192.168.1.4         | [RFC5245]                |
   | 192.168.1.4 64678 typ host             |                          |
   | a=candidate:1 2 UDP  1694302206 24.23.204.141        | [RFC5245]                |
   | 24.23.204.141 64678 typ srflx raddr    |                          |
   | 192.168.1.4 rport 64678                |                          |
   | a=rtcp-fb:109 nack                     | [RFC5104]She adds her    |
   |                                        | her intent for    |
   |                                               | NACK RTCP     |
   |                                        | feedback support         |
   | ****** Video m=line *********          | ************************ |
   |                                        | *****                    |
   | m=video  62445 RTP/AVP 120             | [RFC4566]Alice    |
   |                                               | includes RTP/AVP  |
   |                                        | RTP/AVP video stream     |
   |                                        | description              |
   | c=IN IP4 24.23.204.141                 | [RFC4566]                |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f:e a=fingerprint:sha-256 DC:B8:5F:64:1A:2 | [RFC5245]                |
   | f:7d:f7:c9:c7:70:9d:1f:66:79:a8:07 4:C2:43:F0:A1:58:D0:A1:2C:19:08 :6B:8B |                          |
   | a=rtpmap:120 VP8/90000 :F0:65:5F:78:E2:51:3B:AC:6F:F3:3F:46:1 |                          | [I-D.ietf-payload
   | B:35                                   |                          | -vp8]
   | a=rtpmap:120 VP8/90000                 | [I-D.ietf-payload-vp8]   |
   | a=sendrecv                             | [RFC3264]                |
   | a=rtcp-mux                             | [RFC5761]Alice    |
   |                                               | intends to   |
   |                                        | to perform RTP/RTCP  |
   |                                               | Mux  |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4        | [RFC5245]                |
   | 192.168.1.4 62445 typ host             |                          |
   | a=candidate:1 1 UDP  1694302207 24.23.204.141        | [RFC5245]                |
   | 24.23.204.141 62537 typ srflx raddr    |                          |
   | 192.168.1.4 rport 62445                |                          |
   | a=candidate:0 2 2113667326 192.168.1.4 54721 | [RFC5245]                |
   | 54721 typ host                         |                          |
   | a=candidate:1 2 UDP 1694302206 24.23.204.141         | [RFC5245]                |
   | 24.23.204.141 54721 typ srflx raddr    |                          |
   | 192.168.1.4 rport 54721                |                          |
   | a=rtcp-fb:120 nack pli                 | [RFC5104] Alice          |
   |                                        | indicates support for    |
   |                                        | for Picture loss  |
   |                                               | Indication and  |
   |                                        | and NACK RTCP         |
   |                                               | feedback   |
   | a=rtcp-fb:120 ccm fir                  | [RFC5104]                |
   +-----------------------------------------------+-------------------+
   +----------------------------------------+--------------------------+

                         Table 42: 41: 5.4.5 SDP Offer

   +-----------------------------------------------+-------------------+

   +----------------------------------------+--------------------------+
   | Answer SDP Contents                    | RFC#/Notes               |
   +-----------------------------------------------+-------------------+
   +----------------------------------------+--------------------------+
   | v=0                                    | [RFC4566]                |
   | o=-  16833 0 IN IP4 0.0.0.0            | [RFC4566]                |
   | s=-                                    | [RFC4566]                |
   | t=0 0                                  | [RFC4566]                |
   | a=ice-ufrag:c300d85b                   | [RFC5245]                |
   | a=ice-pwd:de4e99bd291c325921d5d47efbabd9a2 a=ice-                                 | [RFC5245]                |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f:e pwd:de4e99bd291c325921d5d47efbabd9a2   |                          |
   | a=fingerprint:sha-256 BB:05:2F:70:9F:0 | [RFC5245]                |
   | f:6d:f7:c9:c7:70:9d:1f:66:79:a8:07 4:A9:0E:05:E9:26:33:E8:70:88:A2 :19:E2 |                          |
   | :1C:3B:4B:9F:81:E6:B8:5C:F4:A5:A8:D8:7 |                          |
   | 3:04                                   |                          |
   | ****** Audio m=line *********          | ************************ |
   |                                        | *****                    |
   | m=audio 49203 RTP/AVP 109              | [RFC4566] Bob     |
   |                                               | accepts RTP/AVP    |
   |                                        | RTP/AVP based audio      |
   |                                        | stream                   |
   | c=IN IP4 98.248.92.77                  | [RFC4566]                |
   | a=rtpmap:109 opus/48000                |                          |
   | a=ptime:20                             |                          |
   | a=sendrecv                             | [RFC3264]                |
   | a=candidate:0 1 UDP 2113667327 192.168.1.7         | [RFC5245]                |
   | 192.168.1.7 49203 typ host             |                          |
   | a=candidate:1 1 UDP 1694302207 98.248.92.77         | [RFC5245]                |
   | 98.248.92.77 49203 typ srflx raddr     |                          |
   | 192.168.1.7 rport 49203                |                          |
   | a=candidate:0 2 UDP 2113667326 192.168.1.7         | [RFC5245]                |
   | 192.168.1.7 60065 typ host             |                          |
   | a=candidate:1 2 UDP 1694302206 98.248.92.77         | [RFC5245]                |
   | 98.248.92.77 60065 typ srflx raddr     |                          |
   | 192.168.1.7 rport 60065                |                          |
   | ****** Video m=line *********          | ************************ |
   |                                        | *****                    |
   | m=video  63130 RTP/SAVP 120            | [RFC4566] Bob accepts    |
   |                                        | accepts RTP/AVP based video      |
   |                                        | based video stram                    |
   | c=IN IP4 98.248.92.771                 | [RFC4566]                |
   | a=rtpmap:120 VP8/90000                 | [I-D.ietf-payload |
   |                                               | -vp8] [I-D.ietf-payload-vp8]   |
   | a=sendrecv                             | [RFC3264]                |
   | a=candidate:0 1 UDP 2113667327 192.168.1.7         | [RFC5245]                |
   | 192.168.1.7 63130 typ host             |                          |
   | a=candidate:1 1 UDP 1694302207 98.248.92.77         | [RFC5245]                |
   | 98.248.92.77 63130 typ srflx raddr     |                          |
   | 192.168.1.7 rport 63130                |                          |
   | a=candidate:0 2 UDP 2113667326 192.168.1.7         | [RFC5245]                |
   | 192.168.1.7 56607 typ host             |                          |
   | a=candidate:1 2 UDP 1694302206 98.248.92.77         | [RFC5245]                |
   | 98.248.92.77 56607 typ srflx raddr     |                          |
   | 192.168.1.7 rport 56607                |                          |
   +-----------------------------------------------+-------------------+
   +----------------------------------------+--------------------------+

                        Table 43: 42: 5.4.5 SDP Answer

6.  IANA Considerations

   This document requires no actions from IANA.

7.  Acknowledgments

   We would like to thank Justin Uberti, Chris Flo Flo, Paul Kyzivat for
   their detailed review and inputs.

8.  Change Log

   [RFC EDITOR NOTE: Please remove this section when publishing]

   Changes from draft-ietf-rtcweb-sdp-01

   o  Complete face-lift

   o  Added visual markers around m=lines to indicate their type, added
      spacing between tables for aiding readers

   o  Updated table names to indicate offer vs answer

   o  Attempted to align to latest versions of SCTP, BUNDLE, MSID drafts

   o  Added mid header extensions to all the lines

   o  Harmonized BUNDLE semantics and conventions updated.

   Changes from draft-ietf-rtcweb-sdp-00

   o  Updated Simulcast/FEC/RTX examples to use RID framework
   o  Fixed BUNDLE references for a=bundle-only

   Changes from draft-nandakumar-rtcweb-sdp-08

   o  Fixed typos

   o  Moved to a WG version

   Changes from draft-nandakumar-rtcweb-sdp-06 and draft-nandakumar-
   rtcweb-sdp-07

   o  Added clarification on Call-Flow diagram usage

   o  More cleanups

   Changes from draft-nandakumar-rtcweb-sdp-05

   o  Added Ascii chart for all the SDP Eaxamples

   o  Improved text and updated SDP Examples for Simulcast and FEC

   o  Fixed MediaStream ID Semantics SDP Errors

   Changes from draft-nandakumar-rtcweb-sdp-04

   o  Interim version of the draft to avert expiry

   o  Corrected placement of c= line as per RFC4566

   o  Updated simulcast SDP to reflect draft-westerlund-avtcore-rtp-
      simulcast-04

   Changes from draft-nandakumar-rtcweb-sdp-03

   o  Aligned more closely with JSEP version -05

   o  Added Conventions to help readability

   o  Add more examples to clarify BUNDLE use-cases

   Changes from draft-nandakumar-rtcweb-sdp-02

   o  Major refactoring was done to group the examples in to categories

   o  SDP was updated through out to reflect JSEP-04 style of defining
      attributes per m=line than at the session level.

   o  Added 8 new examples.

   o  Updated references for Trickle, Unified Plan

   o  Add section to explain the syntax conventions followed in the
      examples.

   Changes from draft-nandakumar-rtcweb-sdp-01

   o  Updated references to OPUS RTP Payload Specification.

   o  Updated BUNDLE examples based on the latest draft-ietf-mmusic-sdp-
      bundle-negotiation.

   o  Added examples for multiple audio and video flows based on Unified
      Plan.

   o  Added new examples for RTX and FEC streams

   o  Updated Simulcast and SVC examples

   Changes from draft-nandakumar-rtcweb-sdp-00

   o  Fixed editorial comments on the mailing list.

   o  Updated Data-channel SDP information based on draft-ietf-mmusic-
      sctp-sdp.

   o  Updated BUNDLE examples based on draft-ietf-mmusic-sdp-bundle-
      negotiation.

   o  Added examples for few more BUNDLE variants

   o  Added new examples for Simulcast and SVC

9.  Informative References

   [RFC3264]  Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
              with Session Description Protocol (SDP)", RFC 3264, DOI
              10.17487/RFC3264, June 2002,
              <http://www.rfc-editor.org/info/rfc3264>.

   [RFC4145]  Yon, D. and G. Camarillo, "TCP-Based Media Transport in
              the Session Description Protocol (SDP)", RFC 4145, DOI
              10.17487/RFC4145, September 2005,
              <http://www.rfc-editor.org/info/rfc4145>.

   [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
              Description Protocol", RFC 4566, DOI 10.17487/RFC4566,
              July 2006, <http://www.rfc-editor.org/info/rfc4566>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
              RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC5245]  Rosenberg, J., "Interactive Connectivity Establishment
              (ICE): A Protocol for Network Address Translator (NAT)
              Traversal for Offer/Answer Protocols", RFC 5245, DOI
              10.17487/RFC5245, April 2010,
              <http://www.rfc-editor.org/info/rfc5245>.

   [RFC5506]  Johansson, I. and M. Westerlund, "Support for Reduced-Size
              Real-Time Transport Control Protocol (RTCP): Opportunities
              and Consequences", RFC 5506, DOI 10.17487/RFC5506, April
              2009, <http://www.rfc-editor.org/info/rfc5506>.

   [RFC3551]  Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
              Video Conferences with Minimal Control", STD 65, RFC 3551,
              DOI 10.17487/RFC3551, July 2003,
              <http://www.rfc-editor.org/info/rfc3551>.

   [RFC3952]  Duric, A. and S. Andersen, "Real-time Transport Protocol
              (RTP) Payload Format for internet Low Bit Rate Codec
              (iLBC) Speech", RFC 3952, DOI 10.17487/RFC3952, December
              2004, <http://www.rfc-editor.org/info/rfc3952>.

   [RFC4796]  Hautakorpi, J. and G. Camarillo, "The Session Description
              Protocol (SDP) Content Attribute", RFC 4796, DOI 10.17487/
              RFC4796, February 2007,
              <http://www.rfc-editor.org/info/rfc4796>.

   [RFC5761]  Perkins, C. and M. Westerlund, "Multiplexing RTP Data and
              Control Packets on a Single Port", RFC 5761, DOI 10.17487/
              RFC5761, April 2010,
              <http://www.rfc-editor.org/info/rfc5761>.

   [RFC3556]  Casner, S., "Session Description Protocol (SDP) Bandwidth
              Modifiers for RTP Control Protocol (RTCP) Bandwidth", RFC
              3556, DOI 10.17487/RFC3556, July 2003,
              <http://www.rfc-editor.org/info/rfc3556>.

   [RFC5104]  Wenger, S., Chandra, U., Westerlund, M., and B. Burman,
              "Codec Control Messages in the RTP Audio-Visual Profile
              with Feedback (AVPF)", RFC 5104, DOI 10.17487/RFC5104,
              February 2008, <http://www.rfc-editor.org/info/rfc5104>.

   [RFC4588]  Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R.
              Hakenberg, "RTP Retransmission Payload Format", RFC 4588,
              DOI 10.17487/RFC4588, July 2006,
              <http://www.rfc-editor.org/info/rfc4588>.

   [RFC5956]  Begen, A., "Forward Error Correction Grouping Semantics in
              the Session Description Protocol", RFC 5956, DOI 10.17487/
              RFC5956, September 2010,
              <http://www.rfc-editor.org/info/rfc5956>.

   [RFC5888]  Camarillo, G. and H. Schulzrinne, "The Session Description
              Protocol (SDP) Grouping Framework", RFC 5888, DOI
              10.17487/RFC5888, June 2010,
              <http://www.rfc-editor.org/info/rfc5888>.

   [RFC6236]  Johansson, I. and K. Jung, "Negotiation of Generic Image
              Attributes in the Session Description Protocol (SDP)", RFC
              6236, DOI 10.17487/RFC6236, May 2011,
              <http://www.rfc-editor.org/info/rfc6236>.

   [RFC3984]  Wenger, S., Hannuksela, M., Stockhammer, T., Westerlund,
              M., and D. Singer, "RTP Payload Format for H.264 Video",
              RFC 3984, DOI 10.17487/RFC3984, February 2005,
              <http://www.rfc-editor.org/info/rfc3984>.

   [RFC5583]  Schierl, T. and S. Wenger, "Signaling Media Decoding
              Dependency in the Session Description Protocol (SDP)", RFC
              5583, DOI 10.17487/RFC5583, July 2009,
              <http://www.rfc-editor.org/info/rfc5583>.

   [RFC5576]  Lennox, J., Ott, J., and T. Schierl, "Source-Specific
              Media Attributes in the Session Description Protocol
              (SDP)", RFC 5576, DOI 10.17487/RFC5576, June 2009,
              <http://www.rfc-editor.org/info/rfc5576>.

   [RFC3550]  Schulzrinne, H., Casner, S., Frederick, R., and V.
              Jacobson, "RTP: A Transport Protocol for Real-Time
              Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550,
              July 2003, <http://www.rfc-editor.org/info/rfc3550>.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <http://www.rfc-editor.org/info/rfc3261>.

   [RFC2326]  Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time
              Streaming Protocol (RTSP)", RFC 2326, DOI 10.17487/
              RFC2326, April 1998,
              <http://www.rfc-editor.org/info/rfc2326>.

   [RFC3605]  Huitema, C., "Real Time Control Protocol (RTCP) attribute
              in Session Description Protocol (SDP)", RFC 3605, DOI
              10.17487/RFC3605, October 2003,
              <http://www.rfc-editor.org/info/rfc3605>.

   [RFC2833]  Schulzrinne, H. and S. Petrack, "RTP Payload for DTMF
              Digits, Telephony Tones and Telephony Signals", RFC 2833,
              DOI 10.17487/RFC2833, May 2000,
              <http://www.rfc-editor.org/info/rfc2833>.

   [RFC6464]  Lennox, J., Ed., Ivov, E., and E. Marocco, "A Real-time
              Transport Protocol (RTP) Header Extension for Client-to-
              Mixer Audio Level Indication", RFC 6464, DOI 10.17487/
              RFC6464, December 2011,
              <http://www.rfc-editor.org/info/rfc6464>.

   [RFC6465]  Ivov, E., Ed., Marocco, E., Ed., and J. Lennox, "A Real-
              time Transport Protocol (RTP) Header Extension for Mixer-
              to-Client Audio Level Indication", RFC 6465, DOI 10.17487/
              RFC6465, December 2011,
              <http://www.rfc-editor.org/info/rfc6465>.

   [RFC7022]  Begen, A., Perkins, C., Wing, D., and E. Rescorla,
              "Guidelines for Choosing RTP Control Protocol (RTCP)
              Canonical Names (CNAMEs)", RFC 7022, DOI 10.17487/RFC7022,
              September 2013, <http://www.rfc-editor.org/info/rfc7022>.

   [I-D.ietf-mmusic-sdp-bundle-negotiation]
              Holmberg, C., Alvestrand, H., and C. Jennings,
              "Negotiating Media Multiplexing Using the Session
              Description Protocol (SDP)", draft-ietf-mmusic-sdp-bundle-
              negotiation-27
              negotiation-24 (work in progress), February January 2016.

   [I-D.ietf-mmusic-sdp-simulcast]
              Burman, B., Westerlund, M., Nandakumar, S., and M. Zanaty,
              "Using Simulcast in SDP and RTP Sessions", draft-ietf-
              mmusic-sdp-simulcast-04
              mmusic-sdp-simulcast-03 (work in progress), February 2016. October 2015.

   [I-D.ietf-mmusic-rid]
              Thatcher, P., Zanaty, M., Nandakumar, S., Burman, B.,
              Roach, A., and B. Campen, "RTP Payload Format
              Constraints", draft-ietf-mmusic-rid-04 (work in progress),
              February 2016.

   [I-D.ietf-payload-rtp-opus]
              Spittka, J., Vos, K., and J. Valin, "RTP Payload Format
              for the Opus Speech and Audio Codec", draft-ietf-payload-
              rtp-opus-11 (work in progress), April 2015.

   [I-D.ietf-payload-vp8]
              Westin, P., Lundin, H., Glover, M., Uberti, J., and F.
              Galligan, "RTP Payload Format for VP8 Video", draft-ietf-
              payload-vp8-17 (work in progress), September 2015.

   [I-D.ietf-rtcweb-jsep]
              Uberti, J., Jennings, C., and E. Rescorla, "Javascript
              Session Establishment Protocol", draft-ietf-rtcweb-jsep-13 draft-ietf-rtcweb-jsep-12
              (work in progress), March 2016. October 2015.

   [I-D.ietf-mmusic-trickle-ice]
              Ivov, E., Rescorla, E., and J. Uberti, "Trickle ICE:
              Incremental Provisioning of Candidates for the Interactive
              Connectivity Establishment (ICE) Protocol", draft-ietf-
              mmusic-trickle-ice-02 (work in progress), January 2015.

   [I-D.ietf-mmusic-msid]
              Alvestrand, H., "WebRTC MediaStream Identification in the
              Session Description Protocol", draft-ietf-mmusic-msid-12 draft-ietf-mmusic-msid-11
              (work in progress), March 2016. October 2015.

   [I-D.ietf-mmusic-sctp-sdp]
              Holmberg, C., Loreto, S., and G. Camarillo, "Stream
              Control Transmission Protocol (SCTP)-Based Media Transport
              in the Session Description Protocol (SDP)", draft-ietf-
              mmusic-sctp-sdp-16
              mmusic-sctp-sdp-15 (work in progress), February 2016. September 2015.

   [I-D.ietf-rtcweb-data-channel]
              Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data
              Channels", draft-ietf-rtcweb-data-channel-13 (work in
              progress), January 2015.

   [I-D.ietf-payload-flexible-fec-scheme]
              Singh, V., Begen, A., Zanaty, M., and G. Mandyam, "RTP
              Payload Format for Flexible Forward Error Correction
              (FEC)", draft-ietf-payload-flexible-fec-scheme-01 (work in
              progress), October 2015.

   [I-D.ietf-mmusic-mux-exclusive]
              Holmberg, C., "Indicating Exclusive Support of RTP/RTCP
              Multiplexing using SDP", draft-ietf-mmusic-mux-
              exclusive-08 (work in progress), June 2016.

   [WebRTC]   W3C, "WebRTC 1.0: Real-time Communication Between
              Browsers",
              <http://dev.w3.org/2011/webrtc/editor/webrtc.html> , .

Authors' Addresses

   Suhas Nandakumar
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Email: snandaku@cisco.com

   Cullen Jennings
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Phone: +1 408 421-9990
   Email: fluffy@cisco.com