draft-ietf-rtcweb-overview-03.txt   draft-ietf-rtcweb-overview-04.txt 
Network Working Group H. Alvestrand Network Working Group H. Alvestrand
Internet-Draft Google Internet-Draft Google
Intended status: Standards Track March 12, 2012 Intended status: Standards Track June 20, 2012
Expires: September 13, 2012 Expires: December 22, 2012
Overview: Real Time Protocols for Brower-based Applications Overview: Real Time Protocols for Brower-based Applications
draft-ietf-rtcweb-overview-03 draft-ietf-rtcweb-overview-04
Abstract Abstract
This document gives an overview and context of a protocol suite This document gives an overview and context of a protocol suite
intended for use with real-time applications that can be deployed in intended for use with real-time applications that can be deployed in
browsers - "real time communication on the Web". browsers - "real time communication on the Web".
It intends to serve as a starting and coordination point to make sure It intends to serve as a starting and coordination point to make sure
all the parts that are needed to achieve this goal are findable, and all the parts that are needed to achieve this goal are findable, and
that the parts that belong in the Internet protocol suite are fully that the parts that belong in the Internet protocol suite are fully
specified and on the right publication track. specified and on the right publication track.
This work is an attempt to synthesize the input of many people, but
makes no claims to fully represent the views of any of them. All
parts of the document should be regarded as open for discussion,
unless the RTCWEB chairs have declared consensus on an item.
This document is a work item of the RTCWEB working group. This document is a work item of the RTCWEB working group.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo Status of this Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 13, 2012.
This Internet-Draft will expire on December 22, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Principles and Terminology . . . . . . . . . . . . . . . . . . 5 2. Principles and Terminology . . . . . . . . . . . . . . . . . . 5
2.1. Goals of this document . . . . . . . . . . . . . . . . . . 5 2.1. Goals of this document . . . . . . . . . . . . . . . . . . 5
2.2. Relationship between API and protocol . . . . . . . . . . 5 2.2. Relationship between API and protocol . . . . . . . . . . 5
2.3. On interoperability and innovation . . . . . . . . . . . . 6 2.3. On interoperability and innovation . . . . . . . . . . . . 6
2.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7 2.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7
3. Architecture and Functionality groups . . . . . . . . . . . . 8 3. Architecture and Functionality groups . . . . . . . . . . . . 8
4. Data transport . . . . . . . . . . . . . . . . . . . . . . . . 12 4. Data transport . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Data framing and securing . . . . . . . . . . . . . . . . . . 12 5. Data framing and securing . . . . . . . . . . . . . . . . . . 13
6. Data formats . . . . . . . . . . . . . . . . . . . . . . . . . 13 6. Data formats . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Connection management . . . . . . . . . . . . . . . . . . . . 13 7. Connection management . . . . . . . . . . . . . . . . . . . . 13
8. Presentation and control . . . . . . . . . . . . . . . . . . . 14 8. Presentation and control . . . . . . . . . . . . . . . . . . . 14
9. Local system support functions . . . . . . . . . . . . . . . . 14 9. Local system support functions . . . . . . . . . . . . . . . . 14
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
11. Security Considerations . . . . . . . . . . . . . . . . . . . 15 11. Security Considerations . . . . . . . . . . . . . . . . . . . 15
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
13.1. Normative References . . . . . . . . . . . . . . . . . . . 16 13.1. Normative References . . . . . . . . . . . . . . . . . . . 16
13.2. Informative References . . . . . . . . . . . . . . . . . . 17 13.2. Informative References . . . . . . . . . . . . . . . . . . 18
Appendix A. Change log . . . . . . . . . . . . . . . . . . . . . 18 Appendix A. Transport and Middlebox specification . . . . . . . . 19
A.1. Changes from A.1. System-provided interfaces . . . . . . . . . . . . . . . . 19
draft-alvestrand-dispatch-rtcweb-datagram-00 to -01 . . . 18 A.2. Middle box related functions . . . . . . . . . . . . . . . 19
A.2. Changes from draft-alvestrand-dispatch-01 to A.3. Transport protocols implemented . . . . . . . . . . . . . 20
draft-alvestrand-rtcweb-overview-00 . . . . . . . . . . . 18 Appendix B. Change log . . . . . . . . . . . . . . . . . . . . . 20
A.3. Changes from draft-alvestrand-rtcweb-00 to -01 . . . . . . 19 B.1. Changes from
A.4. Changes from draft-alvestrand-rtcweb-overview-01 to draft-alvestrand-dispatch-rtcweb-datagram-00 to -01 . . . 20
draft-ietf-rtcweb-overview-00 . . . . . . . . . . . . . . 19 B.2. Changes from draft-alvestrand-dispatch-01 to
A.5. Changes from -00 to -01 of draft-ietf-rtcweb-overview . . 19 draft-alvestrand-rtcweb-overview-00 . . . . . . . . . . . 20
A.6. Changes from -01 to -02 of draft-ietf-rtcweb-overview . . 19 B.3. Changes from draft-alvestrand-rtcweb-00 to -01 . . . . . . 20
A.7. Changes from -02 to -03 of draft-ietf-rtcweb-overview . . 20 B.4. Changes from draft-alvestrand-rtcweb-overview-01 to
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 20 draft-ietf-rtcweb-overview-00 . . . . . . . . . . . . . . 21
B.5. Changes from -00 to -01 of draft-ietf-rtcweb-overview . . 21
B.6. Changes from -01 to -02 of draft-ietf-rtcweb-overview . . 21
B.7. Changes from -02 to -03 of draft-ietf-rtcweb-overview . . 21
B.8. Changes from -03 to -04 of draft-ietf-rtcweb-overview . . 22
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction 1. Introduction
The Internet was, from very early in its lifetime, considered a The Internet was, from very early in its lifetime, considered a
possible vehicle for the deployment of real-time, interactive possible vehicle for the deployment of real-time, interactive
applications - with the most easily imaginable being audio applications - with the most easily imaginable being audio
conversations (aka "Internet telephony") and videoconferencing. conversations (aka "Internet telephony") and videoconferencing.
The first attempts to build this were dependent on special networks, The first attempts to build this were dependent on special networks,
special hardware and custom-built software, often at very high prices special hardware and custom-built software, often at very high prices
or at low quality, placing great demands on the infrastructure. or at low quality, placing great demands on the infrastructure.
As the available bandwidth has increased, and as processors and other As the available bandwidth has increased, and as processors and other
hardware has become ever faster, the barriers to participation have hardware has become ever faster, the barriers to participation have
decreased, and it is possible to deliver a satisfactory experience on decreased, and it has become possible to deliver a satisfactory
commonly available computing hardware. experience on commonly available computing hardware.
Still, there are a number of barriers to the ability to communicate Still, there are a number of barriers to the ability to communicate
universally - one of these is that there is, as of yet, no single set universally - one of these is that there is, as of yet, no single set
of communication protocols that all agree should be made available of communication protocols that all agree should be made available
for communication; another is the sheer lack of universal for communication; another is the sheer lack of universal
identification systems (such as is served by telephone numbers or identification systems (such as is served by telephone numbers or
email addresses in other communications systems). email addresses in other communications systems).
Development of The Universal Solution has proved hard, however, for Development of The Universal Solution has proved hard, however, for
all the usual reasons. This memo aims to take a more building-block- all the usual reasons.
oriented approach, and try to find consensus on a set of substrate
components that we think will be useful in any real-time
communications systems.
The last few years have also seen a new platform rise for deployment The last few years have also seen a new platform rise for deployment
of services: The browser-embedded application, or "Web application". of services: The browser-embedded application, or "Web application".
It turns out that as long as the browser platform has the necessary It turns out that as long as the browser platform has the necessary
interfaces, it is possible to deliver almost any kind of service on interfaces, it is possible to deliver almost any kind of service on
it. it.
Traditionally, these interfaces have been delivered by plugins, which Traditionally, these interfaces have been delivered by plugins, which
had to be downloaded and installed separately from the browser; in had to be downloaded and installed separately from the browser; in
the development of HTML5, much promise is seen by the possibility of the development of HTML5, application developers see much promise in
making those interfaces available in a standardized way within the the possibility of making those interfaces available in a
browser. standardized way within the browser.
This memo specifies a set of building blocks that can be made This memo describes a set of building blocks that can be made
accessible and controllable through a Javascript API interface in a accessible and controllable through a Javascript API in a browser,
browser, and which together form a necessary and sufficient set of and which together form a sufficient set of functions to allow the
functions to allow the use of interactive audio and video in use of interactive audio and video in applications that communicate
applications that communicate directly between browsers across the directly between browsers across the Internet. The resulting
Internet. The resulting protocol suite is intended to enable all the protocol suite is intended to enable all the applications that are
applications that are described as required scenarios in the RTCWEB described as required scenarios in the RTCWEB use cases document
use cases document [I-D.ietf-rtcweb-use-cases-and-requirements]. [I-D.ietf-rtcweb-use-cases-and-requirements].
Other efforts, for instance the W3C WebRTC, Web Applications and Other efforts, for instance the W3C WebRTC, Web Applications and
Device API working groups, focus on making standardized APIs and Device API working groups, focus on making standardized APIs and
interfaces available, within or alongside the HTML5 effort, for those interfaces available, within or alongside the HTML5 effort, for those
functions; this memo concentrates on specifying the protocols and functions; this memo concentrates on specifying the protocols and
subprotocols that are needed to specify the interactions that happen subprotocols that are needed to specify the interactions that happen
across the network. across the network.
2. Principles and Terminology 2. Principles and Terminology
2.1. Goals of this document 2.1. Goals of this document
The goal of the RTCWEB protocol specification is to specify a set of The goal of the RTCWEB protocol specification is to specify a set of
protocols that, if all are implemented, will allow the implementation protocols that, if all are implemented, will allow an implementation
to communicate with another implementation using audio, video and to communicate with another implementation using audio, video and
auxiliary data sent along the most direct possible path between the data sent along the most direct possible path between the
participants. participants.
This document is intended to serve as the roadmap to the RTCWEB This document is intended to serve as the roadmap to the RTCWEB
specifications. It defines terms used by other pieces of specifications. It defines terms used by other pieces of
specification, lists references to other specifications that don't specification, lists references to other specifications that don't
need further elaboration in the RTCWEB context, and gives pointers to need further elaboration in the RTCWEB context, and gives pointers to
other documents that form part of the RTCWEB suite. other documents that form part of the RTCWEB suite.
By reading this document and the documents it refers to, it should be By reading this document and the documents it refers to, it should be
possible to have all information needed to implement an RTCWEB possible to have all information needed to implement an RTCWEB
skipping to change at page 5, line 50 skipping to change at page 5, line 47
[W3C.WD-webrtc-20120209] [W3C.WD-webrtc-20120209]
Together, these two specifications aim to provide an environment Together, these two specifications aim to provide an environment
where Javascript embedded in any page, viewed in any compatible where Javascript embedded in any page, viewed in any compatible
browser, when suitably authorized by its user, is able to set up browser, when suitably authorized by its user, is able to set up
communication using audio, video and auxiliary data, where the communication using audio, video and auxiliary data, where the
browser environment does not constrain the types of application in browser environment does not constrain the types of application in
which this functionality can be used. which this functionality can be used.
The protocol specification does not assume that all implementations The protocol specification does not assume that all implementations
implement this API; it is not intended to be possible by observing implement this API; it is not intended to be necessary for
the bits on the wire whether they come from a browser or from another interoperation to know whether the entity one is communicating with
device implementing this specification. is a browser or another device implementing this specification.
The goal of cooperation between the protocol specification and the The goal of cooperation between the protocol specification and the
API specification is that for all options and features of the API specification is that for all options and features of the
protocol specification, it should be clear which API calls to make to protocol specification, it should be clear which API calls to make to
exercise that option or feature; similarly, for any sequence of API exercise that option or feature; similarly, for any sequence of API
calls, it should be clear which protocol options and features will be calls, it should be clear which protocol options and features will be
invoked. Both subject to constraints of the implementation, of invoked. Both subject to constraints of the implementation, of
course. course.
2.3. On interoperability and innovation 2.3. On interoperability and innovation
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application through browser APIs. application through browser APIs.
As for all protocol and API specifications, there is no restriction As for all protocol and API specifications, there is no restriction
that the protocols can only be used to talk to another browser; since that the protocols can only be used to talk to another browser; since
they are fully specified, any device that implements the protocols they are fully specified, any device that implements the protocols
faithfully should be able to interoperate with the application faithfully should be able to interoperate with the application
running in the browser. running in the browser.
A commonly imagined model of deployment is the one depicted below. A commonly imagined model of deployment is the one depicted below.
+-----------+ +-----------+ +-----------+ +-----------+
| Web | | Web | | Web | | Web |
| | Signalling | | | | Signalling | |
| |-------------| | | |-------------| |
| Server | path | Server | | Server | path | Server |
| | | | | | | |
+-----------+ +-----------+ +-----------+ +-----------+
/ \ / \
/ \ Application-defined over / \ Application-defined
/ \ HTTP/Websockets / \ over
/ \ / \ HTTP/Websockets
/ Application-defined over \ / Application-defined over \
/ HTTP/Websockets \ / HTTP/Websockets \
/ \ / \
+-----------+ +-----------+ +-----------+ +-----------+
|JS/HTML/CSS| |JS/HTML/CSS| |JS/HTML/CSS| |JS/HTML/CSS|
+-----------+ +-----------+ +-----------+ +-----------+
+-----------+ +-----------+ +-----------+ +-----------+
| | | | | | | |
| | | | | | | |
| Browser | ------------------------- | Browser | | Browser | ------------------------- | Browser |
| | Media path | | | | Media path | |
| | | | | | | |
+-----------+ +-----------+ +-----------+ +-----------+
Figure 2: Browser RTC Trapezoid Figure 2: Browser RTC Trapezoid
On this drawing, the critical part to note is that the media path On this drawing, the critical part to note is that the media path
("low path") goes directly between the browsers, so it has to be ("low path") goes directly between the browsers, so it has to be
conformant to the specifications of the RTCWEB protocol suite; the conformant to the specifications of the RTCWEB protocol suite; the
signalling path ("high path") goes via servers that can modify, signalling path ("high path") goes via servers that can modify,
translate or massage the signals as needed. translate or massage the signals as needed.
If the two Web servers are operated by different entities, the inter- If the two Web servers are operated by different entities, the inter-
skipping to change at page 11, line 41 skipping to change at page 11, line 41
formats, a way to describe them, a session description, is needed. formats, a way to describe them, a session description, is needed.
o Connection management: Setting up connections, agreeing on data o Connection management: Setting up connections, agreeing on data
formats, changing data formats during the duration of a call; SIP formats, changing data formats during the duration of a call; SIP
and Jingle/XMPP belong in this category. and Jingle/XMPP belong in this category.
o Presentation and control: What needs to happen in order to ensure o Presentation and control: What needs to happen in order to ensure
that interactions behave in a non-surprising manner. This can that interactions behave in a non-surprising manner. This can
include floor control, screen layout, voice activated image include floor control, screen layout, voice activated image
switching and other such functions - where part of the system switching and other such functions - where part of the system
require the cooperation between parties. Cisco/Tandberg's TIP was require the cooperation between parties. XCON and Cisco/
one attempt at specifying this functionality. Tandberg's TIP were some attempts at specifying this kind of
functionality; many applications have been built without
standardized interfaces to these functions.
o Local system support functions: These are things that need not be o Local system support functions: These are things that need not be
specified uniformly, because each participant may choose to do specified uniformly, because each participant may choose to do
these in a way of the participant's choosing, without affecting these in a way of the participant's choosing, without affecting
the bits on the wire in a way that others have to be cognizant of. the bits on the wire in a way that others have to be cognizant of.
Examples in this category include echo cancellation (some forms of Examples in this category include echo cancellation (some forms of
it), local authentication and authorization mechanisms, OS access it), local authentication and authorization mechanisms, OS access
control and the ability to do local recording of conversations. control and the ability to do local recording of conversations.
Within each functionality group, it is important to preserve both Within each functionality group, it is important to preserve both
skipping to change at page 12, line 35 skipping to change at page 12, line 36
Data transport refers to the sending and receiving of data over the Data transport refers to the sending and receiving of data over the
network interfaces, the choice of network-layer addresses at each end network interfaces, the choice of network-layer addresses at each end
of the communication, and the interaction with any intermediate of the communication, and the interaction with any intermediate
entities that handle the data, but do not modify it (such as TURN entities that handle the data, but do not modify it (such as TURN
relays). relays).
It includes necessary functions for congestion control: When not to It includes necessary functions for congestion control: When not to
send data. send data.
The data transport protocols used by RTCWEB are described in <WORKING T are described in <WORKING GROUP DRAFT "TRANSPORTS">.
GROUP DRAFT "TRANSPORTS">.
ICE is required for all media paths that use UDP; in addition to the ICE is required for all media paths that use UDP; in addition to the
ability to pass NAT boxes, ICE fulfils the need for guaranteeing that ability to pass NAT boxes, ICE fulfils the need for guaranteeing that
the media path is going to an UDP port that is willing to receive the the media path is going to an UDP port that is willing to receive the
data. data.
The details of interactions with intermediate boxes, such as The data transport protocols used by RTCWEB, as well as the details
firewalls, relays and NAT boxes, is described in <WORKING GROUP DRAFT of interactions with intermediate boxes, such as firewalls, relays
"PEER TO PEER CONNECTIVITY">. and NAT boxes, are intended to be described in a separate document;
for now, notes are gathered in Appendix A.
5. Data framing and securing 5. Data framing and securing
The format for media transport is RTP [RFC3550]. Implementation of The format for media transport is RTP [RFC3550]. Implementation of
SRTP [RFC3711] is required for all implementations. SRTP [RFC3711] is required for all implementations.
The detailed considerations for usage of functions from RTP and SRTP The detailed considerations for usage of functions from RTP and SRTP
are given in [I-D.ietf-rtcweb-rtp-usage]. The security are given in [I-D.ietf-rtcweb-rtp-usage]. The security
considerations for the RTCWEB use case are in considerations for the RTCWEB use case are in
[I-D.ietf-rtcweb-security], and the resulting security functions are [I-D.ietf-rtcweb-security], and the resulting security functions are
described in [I-D.ietf-rtcweb-security-arch] Considerations for the described in [I-D.ietf-rtcweb-security-arch].
transfer of data that is not in RTP format is described in
[I-D.ietf-rtcweb-data-channel], and the resulting protocol is Considerations for the transfer of data that is not in RTP format is
described in [I-D.jesup-rtcweb-data-protocol] (not yet a WG document) described in [I-D.ietf-rtcweb-data-channel], and the resulting
protocol is described in [I-D.jesup-rtcweb-data-protocol] (not yet a
WG document)
6. Data formats 6. Data formats
The intent of this specification is to allow each communications The intent of this specification is to allow each communications
event to use the data formats that are best suited for that event to use the data formats that are best suited for that
particular instance, where a format is supported by both sides of the particular instance, where a format is supported by both sides of the
connection. However, a minimum standard is greatly helpful in order connection. However, a minimum standard is greatly helpful in order
to ensure that communication can be achieved. This document to ensure that communication can be achieved. This document
specifies a minimum baseline that will be supported by all specifies a minimum baseline that will be supported by all
implementations of this specification, and leaves further codecs to implementations of this specification, and leaves further codecs to
skipping to change at page 16, line 22 skipping to change at page 16, line 27
The ones below have made special, identifiable contributions; this The ones below have made special, identifiable contributions; this
does not mean that others' contributions are less important. does not mean that others' contributions are less important.
Thanks to Cary Bran, Cullen Jennings, Colin Perkins, Magnus Thanks to Cary Bran, Cullen Jennings, Colin Perkins, Magnus
Westerlund and Joerg Ott, who offered technical contributions on Westerlund and Joerg Ott, who offered technical contributions on
various versions of the draft. various versions of the draft.
Thanks to Jonathan Rosenberg, Matthew Kaufman and others at Skype for Thanks to Jonathan Rosenberg, Matthew Kaufman and others at Skype for
the ASCII drawings in section 1. the ASCII drawings in section 1.
Thanks to Justin Uberti, Henry Sinnreich, Colin Perkins and Simon Thanks to Eric Rescorla, Justin Uberti, Henry Sinnreich, Colin
Leinen for document review. Perkins and Simon Leinen for document review.
13. References 13. References
13.1. Normative References 13.1. Normative References
[I-D.ietf-mmusic-sctp-sdp]
Loreto, S. and G. Camarillo, "Stream Control Transmission
Protocol (SCTP)-Based Media Transport in the Session
Description Protocol (SDP)", draft-ietf-mmusic-sctp-sdp-00
(work in progress), July 2011.
[I-D.ietf-rtcweb-data-channel] [I-D.ietf-rtcweb-data-channel]
Jesup, R., Loreto, S., and M. Tuexen, "RTCWeb Datagram Jesup, R., Loreto, S., and M. Tuexen, "RTCWeb Datagram
Connection", draft-ietf-rtcweb-data-channel-00 (work in Connection", draft-ietf-rtcweb-data-channel-00 (work in
progress), March 2012. progress), March 2012.
[I-D.ietf-rtcweb-jsep] [I-D.ietf-rtcweb-jsep]
Uberti, J. and C. Jennings, "Javascript Session Uberti, J. and C. Jennings, "Javascript Session
Establishment Protocol", draft-ietf-rtcweb-jsep-00 (work Establishment Protocol", draft-ietf-rtcweb-jsep-00 (work
in progress), March 2012. in progress), March 2012.
[I-D.ietf-rtcweb-rtp-usage] [I-D.ietf-rtcweb-rtp-usage]
Perkins, C., Ott, J., and M. Westerlund, "Web Real-Time Perkins, C., Westerlund, M., and J. Ott, "Web Real-Time
Communication (WebRTC): Media Transport and Use of RTP", Communication (WebRTC): Media Transport and Use of RTP",
draft-ietf-rtcweb-rtp-usage-01 (work in progress), draft-ietf-rtcweb-rtp-usage-01 (work in progress),
October 2011. October 2011.
[I-D.ietf-rtcweb-security] [I-D.ietf-rtcweb-security]
Rescorla, E., "Security Considerations for RTC-Web", Rescorla, E., "Security Considerations for RTC-Web",
draft-ietf-rtcweb-security-01 (work in progress), draft-ietf-rtcweb-security-01 (work in progress),
October 2011. October 2011.
[I-D.ietf-rtcweb-security-arch] [I-D.ietf-rtcweb-security-arch]
Rescorla, E., "RTCWEB Security Architecture", Rescorla, E., "RTCWEB Security Architecture",
draft-ietf-rtcweb-security-arch-00 (work in progress), draft-ietf-rtcweb-security-arch-00 (work in progress),
January 2012. January 2012.
[I-D.nandakumar-rtcweb-stun-uri]
Nandakumar, S., Salgueiro, G., and P. Jones, "URI Scheme
for Session Traversal Utilities for NAT (STUN) Protocol",
draft-nandakumar-rtcweb-stun-uri-00 (work in progress),
October 2011.
[I-D.tuexen-tsvwg-sctp-dtls-encaps]
Jesup, R., Loreto, S., Stewart, R., and M. Tuexen, "DTLS
Encapsulation of SCTP Packets for RTCWEB",
draft-tuexen-tsvwg-sctp-dtls-encaps-00 (work in progress),
March 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, with Session Description Protocol (SDP)", RFC 3264,
June 2002. June 2002.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003. Applications", STD 64, RFC 3550, July 2003.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)", Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, March 2004. RFC 3711, March 2004.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245,
April 2010.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session
Traversal Utilities for NAT (STUN)", RFC 5766, April 2010.
13.2. Informative References 13.2. Informative References
[I-D.cbran-rtcweb-codec] [I-D.cbran-rtcweb-codec]
Bran, C. and C. Jennings, "WebRTC Codec and Media Bran, C. and C. Jennings, "WebRTC Codec and Media
Processing Requirements", draft-cbran-rtcweb-codec-01 Processing Requirements", draft-cbran-rtcweb-codec-01
(work in progress), October 2011. (work in progress), October 2011.
[I-D.ietf-rtcweb-use-cases-and-requirements] [I-D.ietf-rtcweb-use-cases-and-requirements]
Holmberg, C., Eriksson, G., and S. Hakansson, "Web Real- Holmberg, C., Hakansson, S., and G. Eriksson, "Web Real-
Time Communication Use-cases and Requirements", Time Communication Use-cases and Requirements",
draft-ietf-rtcweb-use-cases-and-requirements-06 (work in draft-ietf-rtcweb-use-cases-and-requirements-06 (work in
progress), October 2011. progress), October 2011.
[I-D.jesup-rtcweb-data-protocol] [I-D.jesup-rtcweb-data-protocol]
Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel
Protocol", draft-jesup-rtcweb-data-protocol-00 (work in Protocol", draft-jesup-rtcweb-data-protocol-00 (work in
progress), March 2012. progress), March 2012.
[I-D.rescorla-rtcweb-generic-idp] [I-D.rescorla-rtcweb-generic-idp]
Rescorla, E., "RTCWEB Generic Identity Provider Rescorla, E., "RTCWEB Generic Identity Provider
Interface", draft-rescorla-rtcweb-generic-idp-00 (work in Interface", draft-rescorla-rtcweb-generic-idp-00 (work in
progress), January 2012. progress), January 2012.
[RFC3935] Alvestrand, H., "A Mission Statement for the IETF", [RFC3935] Alvestrand, H., "A Mission Statement for the IETF",
BCP 95, RFC 3935, October 2004. BCP 95, RFC 3935, October 2004.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245,
April 2010.
[W3C.WD-html5-20110525] [W3C.WD-html5-20110525]
Hickson, I., "HTML5", World Wide Web Consortium Hickson, I., "HTML5", World Wide Web Consortium
LastCall WD-html5-20110525, May 2011, LastCall WD-html5-20110525, May 2011,
<http://www.w3.org/TR/2011/WD-html5-20110525>. <http://www.w3.org/TR/2011/WD-html5-20110525>.
[W3C.WD-webrtc-20120209] [W3C.WD-webrtc-20120209]
Bergkvist, A., Burnett, D., Narayanan, A., and C. Bergkvist, A., Burnett, D., Narayanan, A., and C.
Jennings, "WebRTC 1.0: Real-time Communication Between Jennings, "WebRTC 1.0: Real-time Communication Between
Browsers", World Wide Web Consortium WD WD-webrtc- Browsers", World Wide Web Consortium WD WD-webrtc-
20120209, February 2012, 20120209, February 2012,
<http://www.w3.org/TR/2012/WD-webrtc-20120209>. <http://www.w3.org/TR/2012/WD-webrtc-20120209>.
[getusermedia] [getusermedia]
Burnett, D. and A. Narayanan, "getusermedia: Getting Burnett, D. and A. Narayanan, "getusermedia: Getting
access to local devices that can generate multimedia access to local devices that can generate multimedia
streams", December 2011, streams", December 2011,
<http://dev.w3.org/2011/webrtc/editor/getusermedia.html>. <http://dev.w3.org/2011/webrtc/editor/getusermedia.html>.
Appendix A. Change log Appendix A. Transport and Middlebox specification
The draft referred to as "transport and middle boxes" in Section 4
has not been written yet. This appendix contains some keywords to
what it should say; this also serves the purpose of linking to the
drafts-in-progress that are relevant to this specification.
A.1. System-provided interfaces
The protocol specifications used here assume that the following
protocols are available as system-level interfaces:
o UDP. This is the protocol assumed by most protocol elements
described.
o TCP. This is used for HTTP/WebSockets, as well as for TURN/SSL
and ICE-TCP.
For both protocols, we assume the ability to set the DSCP code point
of the sockets opened. We do not assume that the DSCP codepoints
will be honored, and we do assume that they may be zeroed or changed,
since this is a local configuration issue.
We do not assume that the implementation will have access to ICMP or
raw IP.
A.2. Middle box related functions
The primary mechanism to deal with middle boxes is ICE, which is an
appropriate way to deal with NAT boxes and firewalls that accept
traffic from the inside, but only from the outside if it's in
response to inside traffic (simple stateful firewalls).
In order to deal with symmetric NATs, TURN MUST be supported.
In order to deal with firewalls that block all UDP traffic, TURN over
TCP MUST be supported. (QUESTION: What about ICE-TCP?)
The following specifications MUST be supported:
o ICE [RFC5245]
o TURN, including TURN over TCP [[QUESTION: and TURN over TLS]],
[RFC5766].
For referring to ICE servers, we use the STUN URI,
[I-D.nandakumar-rtcweb-stun-uri].
A.3. Transport protocols implemented
For data transport, we implement SCTP over DTLS over ICE. This is
specified in [I-D.tuexen-tsvwg-sctp-dtls-encaps]. Negotiation of
this transport in SCTP is defined in [I-D.ietf-mmusic-sctp-sdp].
Appendix B. Change log
This section may be deleted by the RFC Editor when preparing for This section may be deleted by the RFC Editor when preparing for
publication. publication.
A.1. Changes from draft-alvestrand-dispatch-rtcweb-datagram-00 to -01 B.1. Changes from draft-alvestrand-dispatch-rtcweb-datagram-00 to -01
Added section "On interoperability and innovation" Added section "On interoperability and innovation"
Added data confidentiality and integrity to the "data framing" layer Added data confidentiality and integrity to the "data framing" layer
Added congestion management requirements in the "data transport" Added congestion management requirements in the "data transport"
layer section layer section
Changed need for non-media data from "question: do we need this?" to Changed need for non-media data from "question: do we need this?" to
"Open issue: How do we do this?" "Open issue: How do we do this?"
Strengthened disclaimer that listed codecs are placeholders, not Strengthened disclaimer that listed codecs are placeholders, not
decisions. decisions.
More details on why the "local system support functions" section is More details on why the "local system support functions" section is
there. there.
A.2. Changes from draft-alvestrand-dispatch-01 to B.2. Changes from draft-alvestrand-dispatch-01 to
draft-alvestrand-rtcweb-overview-00 draft-alvestrand-rtcweb-overview-00
Added section on "Relationship between API and protocol" Added section on "Relationship between API and protocol"
Added terminology section Added terminology section
Mentioned congestion management as part of the "data transport" layer Mentioned congestion management as part of the "data transport" layer
in the layer list in the layer list
A.3. Changes from draft-alvestrand-rtcweb-00 to -01 B.3. Changes from draft-alvestrand-rtcweb-00 to -01
Removed most technical content, and replaced with pointers to drafts Removed most technical content, and replaced with pointers to drafts
as requested and identified by the RTCWEB WG chairs. as requested and identified by the RTCWEB WG chairs.
Added content to acknowledgements section. Added content to acknowledgements section.
Added change log. Added change log.
Spell-checked document. Spell-checked document.
A.4. Changes from draft-alvestrand-rtcweb-overview-01 to B.4. Changes from draft-alvestrand-rtcweb-overview-01 to
draft-ietf-rtcweb-overview-00 draft-ietf-rtcweb-overview-00
Changed draft name and document date. Changed draft name and document date.
Removed unused references Removed unused references
A.5. Changes from -00 to -01 of draft-ietf-rtcweb-overview B.5. Changes from -00 to -01 of draft-ietf-rtcweb-overview
Added architecture figures to section 2. Added architecture figures to section 2.
Changed the description of "echo cancellation" under "local system Changed the description of "echo cancellation" under "local system
support functions". support functions".
Added a few more definitions. Added a few more definitions.
A.6. Changes from -01 to -02 of draft-ietf-rtcweb-overview B.6. Changes from -01 to -02 of draft-ietf-rtcweb-overview
Added pointers to use cases, security and rtp-usage drafts (now WG Added pointers to use cases, security and rtp-usage drafts (now WG
drafts). drafts).
Changed description of SRTP from mandatory-to-use to mandatory-to- Changed description of SRTP from mandatory-to-use to mandatory-to-
implement. implement.
Added the "3 principles of negotiation" to the connection management Added the "3 principles of negotiation" to the connection management
section. section.
Added an explicit statement that ICE is required for both NAT and Added an explicit statement that ICE is required for both NAT and
consent-to-receive. consent-to-receive.
A.7. Changes from -02 to -03 of draft-ietf-rtcweb-overview B.7. Changes from -02 to -03 of draft-ietf-rtcweb-overview
Added references to a number of new drafts. Added references to a number of new drafts.
Expanded the description text under the "trapezoid" drawing with some Expanded the description text under the "trapezoid" drawing with some
more text discussed on the list. more text discussed on the list.
Changed the "Connection management" sentence from "will be done using Changed the "Connection management" sentence from "will be done using
SDP offer/answer" to "will be capable of representing SDP offer/ SDP offer/answer" to "will be capable of representing SDP offer/
answer" - this seems more consistent with JSEP. answer" - this seems more consistent with JSEP.
Added "security mechanisms" to the things a non-gatewayed SIP devices Added "security mechanisms" to the things a non-gatewayed SIP devices
must support in order to not need a media gateway. must support in order to not need a media gateway.
Added a definition for "browser". Added a definition for "browser".
B.8. Changes from -03 to -04 of draft-ietf-rtcweb-overview
Made introduction more normative.
Several wording changes in response to review comments from EKR
Added Appendix A to hold references and notes that are not yet in a
separate document.
Author's Address Author's Address
Harald T. Alvestrand Harald T. Alvestrand
Google Google
Kungsbron 2 Kungsbron 2
Stockholm, 11122 Stockholm, 11122
Sweden Sweden
Email: harald@alvestrand.no Email: harald@alvestrand.no
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