draft-ietf-mmusic-data-channel-sdpneg-05.txt   draft-ietf-mmusic-data-channel-sdpneg-06.txt 
MMUSIC K. Drage, Ed. MMUSIC K. Drage, Ed.
Internet-Draft M. Makaraju Internet-Draft M. Makaraju
Intended status: Standards Track J. Stoetzer-Bradler Intended status: Standards Track J. Stoetzer-Bradler
Expires: April 7, 2016 Alcatel-Lucent Expires: April 21, 2016 Alcatel-Lucent
R. Ejzak R. Ejzak
J. Marcon J. Marcon
Unaffiliated Unaffiliated
October 5, 2015 October 19, 2015
SDP-based Data Channel Negotiation SDP-based Data Channel Negotiation
draft-ietf-mmusic-data-channel-sdpneg-05 draft-ietf-mmusic-data-channel-sdpneg-06
Abstract Abstract
The Real-Time Communication in WEB-browsers (RTCWeb) working group is The Real-Time Communication in WEB-browsers (RTCWeb) working group is
charged to provide protocols to support direct interactive rich charged to provide protocols to support direct interactive rich
communications using audio, video, and data between two peers' web- communications using audio, video, and data between two peers' web-
browsers. For the support of data communication, the RTCWeb working browsers. For the support of data communication, the RTCWeb working
group has in particular defined the concept of bi-directional data group has in particular defined the concept of bi-directional data
channels over SCTP, where each data channel might be used to channels over SCTP, where each data channel might be used to
transport other protocols, called sub-protocols. Data channel setup transport other protocols, called sub-protocols. Data channel setup
skipping to change at page 1, line 47 skipping to change at page 1, line 47
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 April 7, 2016. This Internet-Draft will expire on April 21, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 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
skipping to change at page 2, line 29 skipping to change at page 2, line 29
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Applicability Statement . . . . . . . . . . . . . . . . . . . 5 4. Applicability Statement . . . . . . . . . . . . . . . . . . . 5
5. SDP Offer/Answer Negotiation . . . . . . . . . . . . . . . . 5 5. SDP Offer/Answer Negotiation . . . . . . . . . . . . . . . . 5
5.1. SDP Syntax . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. SDP Syntax . . . . . . . . . . . . . . . . . . . . . . . 5
5.1.1. SDP Attribute for Data Channel Parameter Negotiation 5 5.1.1. SDP Attribute for Data Channel Parameter Negotiation 5
5.1.1.1. dcmap Attribute . . . . . . . . . . . . . . . . . 5 5.1.1.1. dcmap Attribute . . . . . . . . . . . . . . . . . 6
5.1.1.2. dcmap Multiplexing Category . . . . . . . . . . . 7 5.1.1.2. dcmap Multiplexing Category . . . . . . . . . . . 8
5.1.1.3. dcmap-stream-id Parameter . . . . . . . . . . . . 7 5.1.1.3. dcmap-stream-id Parameter . . . . . . . . . . . . 8
5.1.1.4. label Parameter . . . . . . . . . . . . . . . . . 7 5.1.1.4. label Parameter . . . . . . . . . . . . . . . . . 8
5.1.1.5. subprotocol Parameter . . . . . . . . . . . . . . 8 5.1.1.5. subprotocol Parameter . . . . . . . . . . . . . . 9
5.1.1.6. max-retr Parameter . . . . . . . . . . . . . . . 8 5.1.1.6. max-retr Parameter . . . . . . . . . . . . . . . 9
5.1.1.7. max-time Parameter . . . . . . . . . . . . . . . 8 5.1.1.7. max-time Parameter . . . . . . . . . . . . . . . 9
5.1.1.8. ordered Parameter . . . . . . . . . . . . . . . . 8 5.1.1.8. ordered Parameter . . . . . . . . . . . . . . . . 9
5.1.2. Sub-Protocol Specific Attributes . . . . . . . . . . 9 5.1.2. Other Media Level Attributes . . . . . . . . . . . . 10
5.1.2.1. dcsa Attribute . . . . . . . . . . . . . . . . . 9 5.1.2.1. dcsa Attribute . . . . . . . . . . . . . . . . . 10
5.1.2.2. dcsa Multiplexing Category . . . . . . . . . . . 10 5.1.2.2. dcsa Multiplexing Category . . . . . . . . . . . 11
5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . 10 5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . 11
5.2.1. Managing Stream Identifiers . . . . . . . . . . . . . 10 5.2.1. Managing Stream Identifiers . . . . . . . . . . . . . 11
5.2.2. Negotiating Data Channel Parameters . . . . . . . . . 11 5.2.2. Negotiating Data Channel Parameters . . . . . . . . . 12
5.2.3. Opening a Data Channel . . . . . . . . . . . . . . . 12 5.2.3. Opening a Data Channel . . . . . . . . . . . . . . . 13
5.2.4. Closing a Data Channel . . . . . . . . . . . . . . . 14 5.2.4. Closing a Data Channel . . . . . . . . . . . . . . . 15
5.2.5. Various SDP Offer/Answer Scenarios and Considerations 15 5.2.5. Various SDP Offer/Answer Scenarios and Considerations 16
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 7. Security Considerations . . . . . . . . . . . . . . . . . . . 19
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
8.1. Subprotocol Identifiers . . . . . . . . . . . . . . . . . 18 8.1. Subprotocol Identifiers . . . . . . . . . . . . . . . . . 19
8.2. New SDP Attributes . . . . . . . . . . . . . . . . . . . 19 8.2. New SDP Attributes . . . . . . . . . . . . . . . . . . . 20
8.2.1. dcmap . . . . . . . . . . . . . . . . . . . . . . . . 19 8.2.1. dcmap . . . . . . . . . . . . . . . . . . . . . . . . 20
8.2.2. dcsa . . . . . . . . . . . . . . . . . . . . . . . . 19 8.2.2. dcsa . . . . . . . . . . . . . . . . . . . . . . . . 20
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21
10. CHANGE LOG . . . . . . . . . . . . . . . . . . . . . . . . . 20 10. CHANGE LOG . . . . . . . . . . . . . . . . . . . . . . . . . 21
10.1. Changes against 'draft-ietf-mmusic-data-channel- 10.1. Changes against 'draft-ietf-mmusic-data-channel-
sdpneg-04' . . . . . . . . . . . . . . . . . . . . . . . 20 sdpneg-05' . . . . . . . . . . . . . . . . . . . . . . . 21
10.2. Changes against 'draft-ietf-mmusic-data-channel- 10.2. Changes against 'draft-ietf-mmusic-data-channel-
sdpneg-03' . . . . . . . . . . . . . . . . . . . . . . . 21 sdpneg-04' . . . . . . . . . . . . . . . . . . . . . . . 22
10.3. Changes against 'draft-ietf-mmusic-data-channel- 10.3. Changes against 'draft-ietf-mmusic-data-channel-
sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 22 sdpneg-03' . . . . . . . . . . . . . . . . . . . . . . . 23
10.4. Changes against 'draft-ietf-mmusic-data-channel- 10.4. Changes against 'draft-ietf-mmusic-data-channel-
sdpneg-01' . . . . . . . . . . . . . . . . . . . . . . . 23 sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 24
10.5. Changes against 'draft-ietf-mmusic-data-channel- 10.5. Changes against 'draft-ietf-mmusic-data-channel-
sdpneg-00' . . . . . . . . . . . . . . . . . . . . . . . 25 sdpneg-01' . . . . . . . . . . . . . . . . . . . . . . . 25
10.6. Changes against 'draft-ejzak-mmusic-data-channel- 10.6. Changes against 'draft-ietf-mmusic-data-channel-
sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 28 sdpneg-00' . . . . . . . . . . . . . . . . . . . . . . . 27
10.7. Changes against '-01' . . . . . . . . . . . . . . . . . 29 10.7. Changes against 'draft-ejzak-mmusic-data-channel-
10.8. Changes against '-00' . . . . . . . . . . . . . . . . . 29 sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 30
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 10.8. Changes against '-01' . . . . . . . . . . . . . . . . . 31
11.1. Normative References . . . . . . . . . . . . . . . . . . 30 10.9. Changes against '-00' . . . . . . . . . . . . . . . . . 31
11.2. Informative References . . . . . . . . . . . . . . . . . 30 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 31
11.1. Normative References . . . . . . . . . . . . . . . . . . 32
11.2. Informative References . . . . . . . . . . . . . . . . . 32
Appendix A. Generic Data Channel Negotiation Aspects When Not Appendix A. Generic Data Channel Negotiation Aspects When Not
Using DCEP . . . . . . . . . . . . . . . . . . . . . 32 Using DCEP . . . . . . . . . . . . . . . . . . . . . 34
A.1. Stream Identifier Numbering . . . . . . . . . . . . . . . 32 A.1. Stream Identifier Numbering . . . . . . . . . . . . . . . 34
A.2. Generic Data Channel Negotiation Not Using DCEP . . . . . 33 A.2. Generic Data Channel Negotiation Not Using DCEP . . . . . 35
A.2.1. Overview . . . . . . . . . . . . . . . . . . . . . . 33 A.2.1. Overview . . . . . . . . . . . . . . . . . . . . . . 35
A.2.2. Opening a Data Channel . . . . . . . . . . . . . . . 33 A.2.2. Opening a Data Channel . . . . . . . . . . . . . . . 35
A.2.3. Closing a Data Channel . . . . . . . . . . . . . . . 34 A.2.3. Closing a Data Channel . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction 1. Introduction
The RTCWeb working group has defined the concept of bi-directional The RTCWeb working group has defined the concept of bi-directional
data channels running on top of SCTP/DTLS. RTCWeb leaves it open for data channels running on top of SCTP/DTLS. RTCWeb leaves it open for
other applications to use data channels and its in-band DCEP or other other applications to use data channels and its in-band DCEP or other
in-band or out-of-band protocols for creating them. Each data in-band or out-of-band protocols for creating them. Each data
channel consists of paired SCTP streams sharing the same SCTP Stream channel consists of paired SCTP streams sharing the same SCTP Stream
Identifier. Data channels are created by endpoint applications Identifier. Data channels are created by endpoint applications
through the WebRTC API, or other users of data channel like CLUE, and through the WebRTC API, or other users of data channel like CLUE, and
skipping to change at page 4, line 9 skipping to change at page 4, line 9
RTCWeb leaves it open how endpoint applications can agree on how to RTCWeb leaves it open how endpoint applications can agree on how to
instantiate a given sub-protocol on a data channel, and whether it is instantiate a given sub-protocol on a data channel, and whether it is
signaled in-band using DCEP or out-of-band using a non-DCEP protocol signaled in-band using DCEP or out-of-band using a non-DCEP protocol
(or both). In particular, the SDP offer generated by the RTCweb data (or both). In particular, the SDP offer generated by the RTCweb data
channel stack includes no channel-specific information. channel stack includes no channel-specific information.
This document defines SDP offer/answer negotiation procedures to This document defines SDP offer/answer negotiation procedures to
establish data channels for transport of well-defined sub-protocols, establish data channels for transport of well-defined sub-protocols,
to enable out-of-band negotiation. to enable out-of-band negotiation.
This document makes use of MSRP in many of the examples. It does not
provide a complete specification of how to negotiate the use of a
data channel to transport MSRP. Procedures specific to each sub-
protocol such as MSRP will be documented elsewhere. The use of MSRP
in some examples is only to show how the generic procedures described
herein might apply to a specific sub-protocol.
2. Conventions 2. Conventions
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 [RFC2119]. document are to be interpreted as described in [RFC2119].
3. Terminology 3. Terminology
This document uses the following terms: This document uses the following terms:
skipping to change at page 7, line 19 skipping to change at page 8, line 19
one 'maxretr-opt' parameter or one 'maxtime-opt' parameter MAY be one 'maxretr-opt' parameter or one 'maxtime-opt' parameter MAY be
present. Both MUST NOT be present. present. Both MUST NOT be present.
5.1.1.2. dcmap Multiplexing Category 5.1.1.2. dcmap Multiplexing Category
Multiplexing characteristics of SDP attributes are described in Multiplexing characteristics of SDP attributes are described in
[I-D.ietf-mmusic-sdp-mux-attributes]. Various SDP attribute [I-D.ietf-mmusic-sdp-mux-attributes]. Various SDP attribute
multiplexing categories are introduced there. multiplexing categories are introduced there.
The multiplexing category of the "a=dcmap:" attribute is SPECIAL. The multiplexing category of the "a=dcmap:" attribute is SPECIAL.
Usage of this attribute is only applicable when associated with
UDP/DTLS/SCTP or TCP/DTLS/SCTP proto SDP "m" lines.
As the usage of multiple SCTP associations on top of a single DTLS As the usage of multiple SCTP associations on top of a single DTLS
connection is outside the scope of [I-D.ietf-mmusic-sctp-sdp], no connection is outside the scope of [I-D.ietf-mmusic-sctp-sdp], no
multiplexing rules are specified for the UDP/DTLS/SCTP and TCP/DTLS/ "a=dcmap:" attribute multiplexing rules are specified for the
SCTP proto values. If future extensions of UDP/DTLS/SCTP and TCP/DTLS/SCTP proto values. This document does
also not specify multiplexing rules for this attribute for SCTP or
SCTP/DTLS proto values. If future extensions of
[I-D.ietf-mmusic-sctp-sdp] define how to negotiate multiplexing of [I-D.ietf-mmusic-sctp-sdp] define how to negotiate multiplexing of
multiple SCTP associations of top of a single DTLS connection, then multiple SCTP associations on top of a single DTLS connection, or how
to add multiple SCTP associations to one BUNDLE group, then
multiplexing rules for the "a=dcmap:" attribute need to be defined as multiplexing rules for the "a=dcmap:" attribute need to be defined as
well, for instance in an extension of this SDP based data channel well, for instance in an extension of this SDP based data channel
negotiation specification. negotiation specification.
5.1.1.3. dcmap-stream-id Parameter 5.1.1.3. dcmap-stream-id Parameter
The 'dcmap-stream-id' parameter indicates the SCTP stream identifier The 'dcmap-stream-id' parameter indicates the SCTP stream identifier
within the SCTP association used to form the data channel. within the SCTP association used to form the data channel.
5.1.1.4. label Parameter 5.1.1.4. label Parameter
skipping to change at page 8, line 10 skipping to change at page 9, line 10
Note: The empty string MAY also be explicitly used as 'label' value, Note: The empty string MAY also be explicitly used as 'label' value,
such that 'label=""' is equivalent to the 'label' parameter not being such that 'label=""' is equivalent to the 'label' parameter not being
present at all. [I-D.ietf-rtcweb-data-protocol] allows the present at all. [I-D.ietf-rtcweb-data-protocol] allows the
DATA_CHANNEL_OPEN message's 'Label' value to be an empty string. DATA_CHANNEL_OPEN message's 'Label' value to be an empty string.
5.1.1.5. subprotocol Parameter 5.1.1.5. subprotocol Parameter
The 'subprotocol' parameter indicates which protocol the client The 'subprotocol' parameter indicates which protocol the client
expects to exchange via the channel. This parameter maps to the expects to exchange via the channel. This parameter maps to the
'Protocol' parameter defined in [I-D.ietf-rtcweb-data-protocol]. 'Protocol' parameter defined in [I-D.ietf-rtcweb-data-protocol].
Section 8.1 specifies how new subprotocol parameter values are Section 8.1 specifies how new sub-protocol parameter values are
registered. 'Subprotocol' is an optional parameter. If the registered. 'Subprotocol' is an optional parameter. If the
'subprotocol' parameter is not present, then its value defaults to 'subprotocol' parameter is not present, then its value defaults to
the empty string. the empty string.
Note: The empty string MAY also be explicitly used as 'subprotocol' Note: The empty string MAY also be explicitly used as 'subprotocol'
value, such that 'subprotocol=""' is equivalent to the 'subprotocol' value, such that 'subprotocol=""' is equivalent to the 'subprotocol'
parameter not being present at all. [I-D.ietf-rtcweb-data-protocol] parameter not being present at all. [I-D.ietf-rtcweb-data-protocol]
allows the DATA_CHANNEL_OPEN message's 'Subprotocol' value to be an allows the DATA_CHANNEL_OPEN message's 'Subprotocol' value to be an
empty string. empty string.
skipping to change at page 9, line 5 skipping to change at page 10, line 5
The 'ordered' parameter with value "true" indicates that the receiver The 'ordered' parameter with value "true" indicates that the receiver
MUST dispatch DATA chunks in the data channel to the upper layer MUST dispatch DATA chunks in the data channel to the upper layer
while preserving the order. The ordered parameter is optional and while preserving the order. The ordered parameter is optional and
takes two values: "true" for ordered and "false" for unordered takes two values: "true" for ordered and "false" for unordered
delivery with "true" as the default value. Any other value is delivery with "true" as the default value. Any other value is
ignored and default "ordered=true" is assumed. In the absence of ignored and default "ordered=true" is assumed. In the absence of
this parameter "ordered=true" is assumed. This parameter maps to the this parameter "ordered=true" is assumed. This parameter maps to the
ordered or unordered data channel types as defined in ordered or unordered data channel types as defined in
[I-D.ietf-rtcweb-data-protocol]. [I-D.ietf-rtcweb-data-protocol].
5.1.2. Sub-Protocol Specific Attributes 5.1.2. Other Media Level Attributes
In the SDP, each data channel declaration MAY also be followed by In the SDP, each data channel declaration MAY also be followed by
other SDP attributes specific to the sub-protocol in use. Each of other media level SDP attributes, which are either specifically
these attributes is represented by one new attribute line, and it defined for or applied to the sub-protocol in use. Each of these
includes the contents of a media-level SDP attribute already defined attributes is represented by one new attribute line, and it includes
for use with this (sub)protocol in another IETF specification. Sub- the contents of a media-level SDP attribute already defined for use
protocol-specific attributes might also be defined for exclusive use with this (sub-)protocol in another IETF specification. Sub-protocol
with data channel transport, but should use the same syntax described specific attributes MAY also be defined for exclusive use with data
here for other sub-protocol-specific attributes. channel transport, but SHOULD use the same syntax described here for
other sub-protocol related attributes.
5.1.2.1. dcsa Attribute 5.1.2.1. dcsa Attribute
Each sub-protocol specific SDP attribute that would normally be used Each sub-protocol related SDP attribute that would normally be used
to negotiate the subprotocol using SDP is replaced with an attribute to negotiate the sub-protocol using SDP is replaced with an attribute
of the form "a=dcsa:stream-id original-attribute", where dcsa stands of the form "a=dcsa:stream-id original-attribute", where dcsa stands
for "data channel sub-protocol attribute", stream-id is the SCTP for "data channel sub-protocol attribute", stream-id is the SCTP
stream identifier assigned to this sub-protocol instance, and stream identifier assigned to this sub-protocol instance, and
original-attribute represents the contents of the sub-protocol original-attribute represents the contents of the sub-protocol
related attribute to be included. related attribute to be included.
The same syntax applies to any other SDP attribute required for
negotiation of this instance of the sub-protocol.
Formal Syntax: Formal Syntax:
Name: dcsa Name: dcsa
Value: dcsa-value Value: dcsa-value
Usage Level: media Usage Level: media
Charset Dependent: no Charset Dependent: no
skipping to change at page 10, line 7 skipping to change at page 11, line 10
Note that the above reference to RFC 4566 defines where the attribute Note that the above reference to RFC 4566 defines where the attribute
definition can be found; it does not provide any limitation on definition can be found; it does not provide any limitation on
support of attributes defined in other documents in accordance with support of attributes defined in other documents in accordance with
this attribute definition. Note however that not all SDP attributes this attribute definition. Note however that not all SDP attributes
are suitable as "a=dcsa:" parameter. [IANA-SDP-Parameters] contains are suitable as "a=dcsa:" parameter. [IANA-SDP-Parameters] contains
the lists of IANA registered session and media level or media level the lists of IANA registered session and media level or media level
only SDP attributes. only SDP attributes.
Thus in the example above, the original attribute line "a=accept- Thus in the example above, the original attribute line "a=accept-
types:text/plain" is represented by the attribute line "a=dcsa:2 types:text/plain" is represented by the attribute line "a=dcsa:2
accept-types:text/plain", which specifies that this instance of MSRP accept-types:text/plain", which specifies that this instance of the
being transported on the SCTP association using the data channel with MSRP sub-protocol being transported on the SCTP association using the
stream id 2 accepts plain text files. data channel with stream id 2 accepts plain text files.
As opposed to the data channel "a=dcmap:" attribute parameters, these As opposed to the data channel "a=dcmap:" attribute parameters, these
parameters are subject to offer/answer negotiation following the parameters are subject to offer/answer negotiation following the
procedures defined in the sub-protocol specific documents. procedures defined in the sub-protocol specific documents.
The same syntax applies to any other SDP attribute required for
negotiation of this instance of the sub-protocol.
Note: This document does not provide a complete specification of how
to negotiate the use of a data channel to transport MSRP. Procedures
specific to each sub-protocol such as MSRP will be documented
elsewhere. The use of MSRP is only an example of how the generic
procedures described herein might apply to a specific sub-protocol.
5.1.2.2. dcsa Multiplexing Category 5.1.2.2. dcsa Multiplexing Category
The multiplexing category of the "a=dcsa:" attribute is SPECIAL. The multiplexing category of the "a=dcsa:" attribute is SPECIAL.
Usage of this attribute is only applicable when associated with
UDP/DTLS/SCTP or TCP/DTLS/SCTP proto SDP "m" lines.
As the usage of multiple SCTP associations on top of a single DTLS As the usage of multiple SCTP associations on top of a single DTLS
connection is outside the scope of [I-D.ietf-mmusic-sctp-sdp], no connection is outside the scope of [I-D.ietf-mmusic-sctp-sdp], no
multiplexing rules are specified for the UDP/DTLS/SCTP and TCP/DTLS/ "a=dcsa:" attribute multiplexing rules are specified for the
SCTP proto values. If future extensions of UDP/DTLS/SCTP and TCP/DTLS/SCTP proto values. This document does
also not specify multiplexing rules for this attribute for SCTP or
SCTP/DTLS proto values. If future extensions of
[I-D.ietf-mmusic-sctp-sdp] define how to negotiate multiplexing of [I-D.ietf-mmusic-sctp-sdp] define how to negotiate multiplexing of
multiple SCTP associations of top of a single DTLS connection, then multiple SCTP associations on top of a single DTLS connection, or how
to add multiple SCTP associations to one BUNDLE group, then
multiplexing rules for the "a=dcsa:" attribute need to be defined as multiplexing rules for the "a=dcsa:" attribute need to be defined as
well, for instance in an extension of this SDP based data channel well, for instance in an extension of this SDP based data channel
negotiation specification. negotiation specification.
5.2. Procedures 5.2. Procedures
5.2.1. Managing Stream Identifiers 5.2.1. Managing Stream Identifiers
If an SDP offer/answer exchange (could be the initial or a subsequent If an SDP offer/answer exchange (could be the initial or a subsequent
one) results in a UDP/DTLS/SCTP or TCP/DTLS/SCTP based media one) results in a UDP/DTLS/SCTP or TCP/DTLS/SCTP based media
skipping to change at page 11, line 39 skipping to change at page 12, line 37
channel is achieved by including only one of 'max-retr' or 'max- channel is achieved by including only one of 'max-retr' or 'max-
time'. By definition max-retr and max-time are mutually exclusive, time'. By definition max-retr and max-time are mutually exclusive,
so at most one of them MAY be present in the "a=dcmap:" attribute so at most one of them MAY be present in the "a=dcmap:" attribute
line. If an SDP offer contains both of these parameters then the line. If an SDP offer contains both of these parameters then the
receiver of such an SDP offer MUST reject the SDP offer. If an SDP receiver of such an SDP offer MUST reject the SDP offer. If an SDP
answer contains both of these parameters then the offerer MAY treat answer contains both of these parameters then the offerer MAY treat
it as an error and MAY assume the associated SDP offer/answer failed it as an error and MAY assume the associated SDP offer/answer failed
and MAY take appropriate recovery actions. These recovery options and MAY take appropriate recovery actions. These recovery options
are outside the scope of this specification. are outside the scope of this specification.
The SDP answer SHALL echo the same subprotocol, max-retr, max-time, The SDP answer SHALL echo the same sub-protocol, max-retr, max-time,
ordered parameters, if those were present in the offer, and MAY ordered parameters, if those were present in the offer, and MAY
include a label parameter. They MAY appear in any order, which could include a label parameter. They MAY appear in any order, which could
be different from the SDP offer, in the SDP answer. be different from the SDP offer, in the SDP answer.
When sending a subsequent offer or an answer, and for as long as the When sending a subsequent offer or an answer, and for as long as the
data channel is still open, the sender MUST replicate the same data channel is still open, the sender MUST replicate the same
information. information.
Data channel types defined in [I-D.ietf-rtcweb-data-protocol] are Data channel types defined in [I-D.ietf-rtcweb-data-protocol] are
mapped to SDP in the following manner, where "ordered=true" is the mapped to SDP in the following manner, where "ordered=true" is the
skipping to change at page 18, line 49 skipping to change at page 19, line 49
7. Security Considerations 7. Security Considerations
No security considerations are envisaged beyond those already No security considerations are envisaged beyond those already
documented in [RFC4566]. documented in [RFC4566].
8. IANA Considerations 8. IANA Considerations
8.1. Subprotocol Identifiers 8.1. Subprotocol Identifiers
Registration of new subprotocol identifiers is performed using the Registration of new sub-protocol identifiers is performed using the
existing IANA table "WebSocket Subprotocol Name Registry". existing IANA table "WebSocket Subprotocol Name Registry".
The following text should be added following the title of the table. The following text should be added following the title of the table.
"This table also includes subprotocol identifiers specified for usage "This table also includes subprotocol identifiers specified for usage
within a WebRTC data channel." within a WebRTC data channel."
The following reference should be added to under the heading The following reference should be added to under the heading
reference: "RFC XXXX". reference: "RFC XXXX".
skipping to change at page 19, line 33 skipping to change at page 20, line 33
This document defines a new SDP media-level attribute "a=dcmap:" as This document defines a new SDP media-level attribute "a=dcmap:" as
follows: follows:
+---------------------+-----------------------------------------+ +---------------------+-----------------------------------------+
| Attribute name: | dcmap | | Attribute name: | dcmap |
| Type of attribute: | media | | Type of attribute: | media |
| Mux category: | SPECIAL | | Mux category: | SPECIAL |
| Charset Dependent: | No | | Charset Dependent: | No |
| Purpose: | Define data channel specific parameters | | Purpose: | Define data channel specific parameters |
| Appropriate values: | As defined in Section 5.1.1 | | Appropriate values: | As defined in Section 5.1.1 |
| Contact name: | Maridi R. Makaraju (Raju) | | Contact name: | MMUSIC Chairs |
| Contact e-mail: | Raju.Makaraju@alcatel-lucent.com | | Contact e-mail: | mmusic-chairs@ietf.org |
| Reference: | RFCXXXX | | Reference: | RFCXXXX |
+---------------------+-----------------------------------------+ +---------------------+-----------------------------------------+
8.2.2. dcsa 8.2.2. dcsa
NOTE to RFC Editor: Please replace "XXXX" with the number of this NOTE to RFC Editor: Please replace "XXXX" with the number of this
RFC. RFC.
This document defines a new SDP media-level attribute "a=dcsa:" as This document defines a new SDP media-level attribute "a=dcsa:" as
follows: follows:
+---------------------+---------------------------------------------+ +---------------------+---------------------------------------------+
| Attribute name: | dcsa | | Attribute name: | dcsa |
| Type of attribute: | media | | Type of attribute: | media |
| Mux category: | SPECIAL | | Mux category: | SPECIAL |
| Charset Dependent: | No | | Charset Dependent: | No |
| Purpose: | Define data channel sub-protocol specific | | Purpose: | Define data channel sub-protocol specific |
| | attributes | | | attributes |
| Appropriate values: | As defined in Section 5.1.2 | | Appropriate values: | As defined in Section 5.1.2 |
| Contact name: | Maridi R. Makaraju (Raju) | | Contact name: | MMUSIC Chairs |
| Contact e-mail: | Raju.Makaraju@alcatel-lucent.com | | Contact e-mail: | mmusic-chairs@ietf.org |
| Reference: | RFCXXXX | | Reference: | RFCXXXX |
+---------------------+---------------------------------------------+ +---------------------+---------------------------------------------+
9. Acknowledgments 9. Acknowledgments
The authors wish to acknowledge the borrowing of ideas from other The authors wish to acknowledge the borrowing of ideas from other
internet drafts by Salvatore Loreto, Gonzalo Camarillo, Peter Dunkley internet drafts by Salvatore Loreto, Gonzalo Camarillo, Peter Dunkley
and Gavin Llewellyn, and to thank Roni Even, Christian Groves, and Gavin Llewellyn, and to thank Roni Even, Christian Groves, Gunnar
Christer Holmberg, Paul Kyzivat, Jonathan Lennox, and Uwe Hellstrom, Christer Holmberg, Paul Kyzivat, Jonathan Lennox, and Uwe
Rauschenbach for their invaluable comments. Rauschenbach for their invaluable comments.
10. CHANGE LOG 10. CHANGE LOG
10.1. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-04' 10.1. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-05'
o In IANA registration Section 8.2.1 and Section 8.2.2 replacement
of contact name and e-mail address with "MMUSIC Chairs" and
"mmusic-chairs@ietf.org".
o In Section 5.1.2.1 replacement of "Thus in the example above, the
original attribute line "a=accept- types:text/plain" is
represented by the attribute line "a=dcsa:2 accept-types:text/
plain", which specifies that this instance of MSRP being
transported on the SCTP association using the data channel with
stream id 2 accepts plain text files." with "... which specifies
that this instance of the MSRP sub-protocol being transported
...".
o The last paragraph of Section 5.1.2.1 started with "Note: This
document does not provide a complete specification ...". Removal
of "Note:" and move of this paragraph to the introduction in
Section 1 as last paragraph.
o Section 5.1.2's headline was "Sub-Protocol Specific Attributes".
Change of this headline to "Other Media Level Attributes" and
adaptations of the first paragraph of this section and the first
paragraph of Section 5.1.2.1 in order to clarify that not only
those attributes may be encapsulated in a "dcsa" attribute, which
are specifically defined for the sub-protocol, but that also other
attributes may be encapsulated if they are related to the specific
sub-protocol instance.
o Move of the last but one paragraph of Section 5.1.2.1 starting
with "The same syntax applies to ..." right in front of the formal
syntax definition of the "dcsa" attribute.
o Modifications of the text in Section 5.1.1.2 and Section 5.1.2.2
in order not to explicitly restrict usage of the "a=dcmap:" and
"a=dcsa:" attributes to "m" lines with proto values "UDP/DTLS/
SCTP" or "TCP/DTLS/SCTP".
10.2. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-04'
o In Section 5.1.1.5 the first (and only) paragraph was "The o In Section 5.1.1.5 the first (and only) paragraph was "The
'subprotocol' parameter indicates which protocol the client 'subprotocol' parameter indicates which protocol the client
expects to exchange via the channel. 'Subprotocol' is an optional expects to exchange via the channel. 'Subprotocol' is an optional
parameter. If the 'subprotocol' parameter is not present, then parameter. If the 'subprotocol' parameter is not present, then
its value defaults to the empty string." Replacement of this its value defaults to the empty string." Replacement of this
paragraph with following two paragraphs: paragraph with following two paragraphs:
* The 'subprotocol' parameter indicates which protocol the client * The 'subprotocol' parameter indicates which protocol the client
expects to exchange via the channel. This parameter maps to expects to exchange via the channel. This parameter maps to
the 'Protocol' parameter defined in the 'Protocol' parameter defined in
[I-D.ietf-rtcweb-data-protocol]. Section 8.1 specifies how new [I-D.ietf-rtcweb-data-protocol]. Section 8.1 specifies how new
subprotocol parameter values are registered. 'Subprotocol' is sub-protocol parameter values are registered. 'Subprotocol' is
an optional parameter. If the 'subprotocol' parameter is not an optional parameter. If the 'subprotocol' parameter is not
present, then its value defaults to the empty string. present, then its value defaults to the empty string.
* Note: The empty string MAY also be explicitly used as * Note: The empty string MAY also be explicitly used as
'subprotocol' value, such that 'subprotocol=""' is equivalent 'subprotocol' value, such that 'subprotocol=""' is equivalent
to the 'subprotocol' parameter not being present at all. to the 'subprotocol' parameter not being present at all.
[I-D.ietf-rtcweb-data-protocol] allows the DATA_CHANNEL_OPEN [I-D.ietf-rtcweb-data-protocol] allows the DATA_CHANNEL_OPEN
message's 'Subprotocol' value to be an empty string. message's 'Subprotocol' value to be an empty string.
o Addition of [I-D.ietf-mmusic-sdp-mux-attributes] to list the of o Addition of [I-D.ietf-mmusic-sdp-mux-attributes] to list the of
skipping to change at page 21, line 20 skipping to change at page 23, line 10
o Addition of new Section 5.1.1.2 describing the mux category of the o Addition of new Section 5.1.1.2 describing the mux category of the
dcmap SDP attribute. This section and the new "a=dcsa:" attribute dcmap SDP attribute. This section and the new "a=dcsa:" attribute
related mux category section are similar to the "Mux Category" related mux category section are similar to the "Mux Category"
sections of the "a=sctp-port:" and "a=max-message-size:" sections of the "a=sctp-port:" and "a=max-message-size:"
attributes in [I-D.ietf-mmusic-sctp-sdp]. attributes in [I-D.ietf-mmusic-sctp-sdp].
o Addition of new Section 5.1.2.2 describing the mux category of the o Addition of new Section 5.1.2.2 describing the mux category of the
dcsa SDP attribute. dcsa SDP attribute.
10.2. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-03' 10.3. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-03'
o In Section 1 replacement of "RTCWeb leaves it open for other o In Section 1 replacement of "RTCWeb leaves it open for other
applications to use data channels and its in-band DCEP or out-of- applications to use data channels and its in-band DCEP or out-of-
band non-DCEP protocols for creating them" with "... to use data band non-DCEP protocols for creating them" with "... to use data
channels and its in-band DCEP or other in-band or out-of-band channels and its in-band DCEP or other in-band or out-of-band
protocols for creating them". Additionally replacement of "In protocols for creating them". Additionally replacement of "In
particular, the SDP offer generated by the application includes no particular, the SDP offer generated by the application includes no
channel-specific information" with "... generated by the RTCweb channel-specific information" with "... generated by the RTCweb
data channel stack includes no channel-specific information". data channel stack includes no channel-specific information".
skipping to change at page 22, line 30 skipping to change at page 24, line 20
o In Section 5.2.1 replacement of "However, an SDP offer/answer o In Section 5.2.1 replacement of "However, an SDP offer/answer
exchange MUST NOT be initiated if the associated SCTP stream is exchange MUST NOT be initiated if the associated SCTP stream is
already negotiated via DCEP" with "However, an SCTP stream MUST already negotiated via DCEP" with "However, an SCTP stream MUST
NOT be referenced in a dcmap or dcsa attribute of an SDP offer/ NOT be referenced in a dcmap or dcsa attribute of an SDP offer/
answer exchange if the associated SCTP stream has already been answer exchange if the associated SCTP stream has already been
negotiated via DCEP". negotiated via DCEP".
o In the examples in Section 6 addition of the previously missing o In the examples in Section 6 addition of the previously missing
colons to the "a=sctp-port" attribute lines. colons to the "a=sctp-port" attribute lines.
10.3. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-02' 10.4. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-02'
o Move of reference [I-D.ietf-rtcweb-jsep] from the list of o Move of reference [I-D.ietf-rtcweb-jsep] from the list of
normative references to the list of informative references. normative references to the list of informative references.
o Addition of [IANA-SDP-Parameters] to the list of informative o Addition of [IANA-SDP-Parameters] to the list of informative
references and addition of following two sentences to the first references and addition of following two sentences to the first
paragraph after the ABNF definition: "Note however that not all paragraph after the ABNF definition: "Note however that not all
SDP attributes are suitable as "a=dcsa:" parameter. SDP attributes are suitable as "a=dcsa:" parameter.
[IANA-SDP-Parameters] contains the lists of IANA registered [IANA-SDP-Parameters] contains the lists of IANA registered
session and media level or media level only SDP attributes." session and media level or media level only SDP attributes."
skipping to change at page 23, line 31 skipping to change at page 25, line 21
a=dcmap". a=dcmap".
o Move of reference [WebRtcAPI] from list of normative references to o Move of reference [WebRtcAPI] from list of normative references to
list of informative references. list of informative references.
o Removal of almost all text parts, which discussed JavaScript or o Removal of almost all text parts, which discussed JavaScript or
other API specific aspects. Such API specific aspects were mainly other API specific aspects. Such API specific aspects were mainly
discussed in sub-sections of Section 5 and Section 5 of draft- discussed in sub-sections of Section 5 and Section 5 of draft-
ietf-mmusic-data-channel-sdpneg-02. ietf-mmusic-data-channel-sdpneg-02.
10.4. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-01' 10.5. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-01'
o New Section 4 regarding applicability to SDP offer/answer only. o New Section 4 regarding applicability to SDP offer/answer only.
o Addition of new Section 8.1 "Subprotocol identifiers" as o Addition of new Section 8.1 "Subprotocol identifiers" as
subsection of the "IANA Considerations" related Section 8. Also subsection of the "IANA Considerations" related Section 8. Also
removal of the temporary note "To be completed. As [I-D.ietf- removal of the temporary note "To be completed. As [I-D.ietf-
rtcweb-data-protocol] this document should refer to IANA's rtcweb-data-protocol] this document should refer to IANA's
WebSocket Subprotocol Name Registry defined in [RFC6455]." WebSocket Subprotocol Name Registry defined in [RFC6455]."
o In Section 5.2.2: o In Section 5.2.2:
skipping to change at page 25, line 36 skipping to change at page 27, line 29
* In the last but one paragraph replacement of "must" with "The * In the last but one paragraph replacement of "must" with "The
application MUST also close...". application MUST also close...".
o In Section 5.1.2 addition of following note after the formal o In Section 5.1.2 addition of following note after the formal
definition of the 'a=dcsa' attribute: "Note that the above definition of the 'a=dcsa' attribute: "Note that the above
reference to RFC 4566 defines were the attribute definition can be reference to RFC 4566 defines were the attribute definition can be
found; it does not provide any limitation on support of attributes found; it does not provide any limitation on support of attributes
defined in other documents in accordance with this attribute defined in other documents in accordance with this attribute
definition." definition."
10.5. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-00' 10.6. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-00'
o In Section 3 "WebRTC data channel" was defined as "A bidirectional o In Section 3 "WebRTC data channel" was defined as "A bidirectional
channel consisting of paired SCTP outbound and inbound streams." channel consisting of paired SCTP outbound and inbound streams."
Replacement of this definition with "Data channel: A WebRTC data Replacement of this definition with "Data channel: A WebRTC data
channel as specified in [I-D.ietf-rtcweb-data-channel]", and channel as specified in [I-D.ietf-rtcweb-data-channel]", and
consistent usage of "data channel" in the remainder of the consistent usage of "data channel" in the remainder of the
document including the document's headline." document including the document's headline."
o In Section 5 removal of following note: 'OPEN ISSUE: The syntax in o In Section 5 removal of following note: 'OPEN ISSUE: The syntax in
[I-D.ietf-mmusic-sctp-sdp] may change as that document progresses. [I-D.ietf-mmusic-sctp-sdp] may change as that document progresses.
skipping to change at page 28, line 22 skipping to change at page 30, line 14
to handle cases where a successful SDP answer is not received, in to handle cases where a successful SDP answer is not received, in
which case the state of the session SHOULD be kept per the last which case the state of the session SHOULD be kept per the last
successful SDP offer/answer." successful SDP offer/answer."
o Although dedicated to "a=dcmap" and "a=dcsa" SDP syntax aspects o Although dedicated to "a=dcmap" and "a=dcsa" SDP syntax aspects
Section 5.1.1 contained already procedural descriptions related to Section 5.1.1 contained already procedural descriptions related to
data channel reliability negotiation. Creation of new data channel reliability negotiation. Creation of new
Section 5.2.2 and moval of reliability negotiation related text to Section 5.2.2 and moval of reliability negotiation related text to
this new section. this new section.
10.6. Changes against 'draft-ejzak-mmusic-data-channel-sdpneg-02' 10.7. Changes against 'draft-ejzak-mmusic-data-channel-sdpneg-02'
o Removal of note "[ACTION ITEM]" from section "subprotocol o Removal of note "[ACTION ITEM]" from section "subprotocol
parameter". As [I-D.ietf-rtcweb-data-protocol] this document parameter". As [I-D.ietf-rtcweb-data-protocol] this document
should refer to IANA's WebSocket Subprotocol Name Registry defined should refer to IANA's WebSocket Subprotocol Name Registry defined
in [RFC6455]. in [RFC6455].
o In whole document, replacement of "unreliable" with "partially o In whole document, replacement of "unreliable" with "partially
reliable", which is used in [I-D.ietf-rtcweb-data-channel] and in reliable", which is used in [I-D.ietf-rtcweb-data-channel] and in
[I-D.ietf-rtcweb-data-protocol] in most places. [I-D.ietf-rtcweb-data-protocol] in most places.
skipping to change at page 29, line 24 skipping to change at page 31, line 16
o In the "Examples" section, in the first two SDP offer examples in o In the "Examples" section, in the first two SDP offer examples in
the a=dcmap attribute lines 'label="BGCP"' was replaced with the a=dcmap attribute lines 'label="BGCP"' was replaced with
'label="BFCP"'. 'label="BFCP"'.
o In all examples, the "m" line proto value "DTLS/SCTP" was replaced o In all examples, the "m" line proto value "DTLS/SCTP" was replaced
with "UDP/DTLS/SCTP" and the "a=fmtp" attribute lines were with "UDP/DTLS/SCTP" and the "a=fmtp" attribute lines were
replaced with "a=max-message-size" attribute lines, as per draft- replaced with "a=max-message-size" attribute lines, as per draft-
ietf-mmusic-sctp-sdp-12. ietf-mmusic-sctp-sdp-12.
10.7. Changes against '-01' 10.8. Changes against '-01'
o Formal syntax for dcmap and dcsa attribute lines. o Formal syntax for dcmap and dcsa attribute lines.
o Making subprotocol as an optional parameter in dcmap. o Making subprotocol as an optional parameter in dcmap.
o Specifying disallowed parameter combinations for max-time and max- o Specifying disallowed parameter combinations for max-time and max-
retr. retr.
o Clarifications on WebRTC data channel close procedures. o Clarifications on WebRTC data channel close procedures.
10.8. Changes against '-00' 10.9. Changes against '-00'
o Revisions to identify difference between internal and external o Revisions to identify difference between internal and external
negotiation and their usage. negotiation and their usage.
o Introduction of more generic terminology, e.g. "application" o Introduction of more generic terminology, e.g. "application"
instead of "browser". instead of "browser".
o Clarification of how "max-retr and max-time affect the usage of o Clarification of how "max-retr and max-time affect the usage of
unreliable and reliable WebRTC data channels. unreliable and reliable WebRTC data channels.
skipping to change at page 31, line 42 skipping to change at page 33, line 38
<http://www.rfc-editor.org/info/rfc6455>. <http://www.rfc-editor.org/info/rfc6455>.
[RFC6714] Holmberg, C., Blau, S., and E. Burger, "Connection [RFC6714] Holmberg, C., Blau, S., and E. Burger, "Connection
Establishment for Media Anchoring (CEMA) for the Message Establishment for Media Anchoring (CEMA) for the Message
Session Relay Protocol (MSRP)", RFC 6714, Session Relay Protocol (MSRP)", RFC 6714,
DOI 10.17487/RFC6714, August 2012, DOI 10.17487/RFC6714, August 2012,
<http://www.rfc-editor.org/info/rfc6714>. <http://www.rfc-editor.org/info/rfc6714>.
[I-D.ietf-rtcweb-jsep] [I-D.ietf-rtcweb-jsep]
Uberti, J., Jennings, C., and E. Rescorla, "Javascript Uberti, J., Jennings, C., and E. Rescorla, "Javascript
Session Establishment Protocol", draft-ietf-rtcweb-jsep-11 Session Establishment Protocol", draft-ietf-rtcweb-jsep-12
(work in progress), July 2015. (work in progress), October 2015.
[IANA-SDP-Parameters] [IANA-SDP-Parameters]
"Session Description Protocol (SDP) Parameters", Internet "Session Description Protocol (SDP) Parameters", Internet
Assigned Numbers Authority Protocol Assignments Session Assigned Numbers Authority Protocol Assignments Session
Description Protocol (SDP) Parameters, Description Protocol (SDP) Parameters,
<http://www.iana.org/assignments/sdp-parameters/ <http://www.iana.org/assignments/sdp-parameters/
sdp-parameters.xhtml>. sdp-parameters.xhtml>.
[WebRtcAPI] [WebRtcAPI]
Bergkvist, A., Burnett, D., Jennings, C., and A. Bergkvist, A., Burnett, D., Jennings, C., and A.
 End of changes. 41 change blocks. 
101 lines changed or deleted 145 lines changed or added

This html diff was produced by rfcdiff 1.42. The latest version is available from http://tools.ietf.org/tools/rfcdiff/