Diff: draft-ietf-mmusic-data-channel-sdpneg-11.txt - draft-ietf-mmusic-data-channel-sdpneg-12.txt

	draft-ietf-mmusic-data-channel-sdpneg-11.txt		draft-ietf-mmusic-data-channel-sdpneg-12.txt

	MMUSIC K. Drage, Ed.		MMUSIC K. Drage, Ed.
	Internet-Draft M. Makaraju		Internet-Draft M. Makaraju
	Intended status: Standards Track Nokia		Intended status: Standards Track Nokia

	Expires: July 19, 2017 J. Stoetzer-Bradler		Expires: September 19, 2017 J. Stoetzer-Bradler

	R. Ejzak		R. Ejzak
	J. Marcon		J. Marcon
	Unaffiliated		Unaffiliated

	January 15, 2017		March 27, 2017

	SDP-based Data Channel Negotiation		SDP-based Data Channel Negotiation

	draft-ietf-mmusic-data-channel-sdpneg-11		draft-ietf-mmusic-data-channel-sdpneg-12

	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 (Stream Control Transmission Protocol), where each		channels over SCTP (Stream Control Transmission Protocol), where each
	data channel might be used to transport other protocols, called		data channel might be used to transport other protocols, called

	skipping to change at page 2, line 4 ¶		skipping to change at page 2, line 4 ¶

	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 July 12, 2017.		This Internet-Draft will expire on September 19, 2017.

	Copyright Notice		Copyright Notice

	Copyright (c) 2017 IETF Trust and the persons identified as the		Copyright (c) 2017 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 49 ¶		skipping to change at page 2, line 49 ¶
	5.1.2. Other Media Level Attributes . . . . . . . . . . . . 10		5.1.2. Other Media Level Attributes . . . . . . . . . . . . 10
	5.1.2.1. dcsa Attribute . . . . . . . . . . . . . . . . . 10		5.1.2.1. dcsa Attribute . . . . . . . . . . . . . . . . . 10
	5.1.2.2. dcsa Multiplexing Category . . . . . . . . . . . 12		5.1.2.2. dcsa Multiplexing Category . . . . . . . . . . . 12
	5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . 12		5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . 12
	5.2.1. Managing Stream Identifiers . . . . . . . . . . . . . 12		5.2.1. Managing Stream Identifiers . . . . . . . . . . . . . 12
	5.2.2. Negotiating Data Channel Parameters . . . . . . . . . 13		5.2.2. Negotiating Data Channel Parameters . . . . . . . . . 13
	5.2.3. Opening a Data Channel . . . . . . . . . . . . . . . 14		5.2.3. Opening a Data Channel . . . . . . . . . . . . . . . 14
	5.2.4. Closing a Data Channel . . . . . . . . . . . . . . . 16		5.2.4. Closing a Data Channel . . . . . . . . . . . . . . . 16
	5.2.5. Various SDP Offer/Answer Scenarios and Considerations 17		5.2.5. Various SDP Offer/Answer Scenarios and Considerations 17
	6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 18		6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 18

	7. Security Considerations . . . . . . . . . . . . . . . . . . . 21		7. Security Considerations . . . . . . . . . . . . . . . . . . . 20
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
	8.1. Subprotocol Identifiers . . . . . . . . . . . . . . . . . 22		8.1. Subprotocol Identifiers . . . . . . . . . . . . . . . . . 21
	8.2. New SDP Attributes . . . . . . . . . . . . . . . . . . . 22		8.2. New SDP Attributes . . . . . . . . . . . . . . . . . . . 21
	8.2.1. dcmap . . . . . . . . . . . . . . . . . . . . . . . . 22		8.2.1. dcmap . . . . . . . . . . . . . . . . . . . . . . . . 21
	8.2.2. dcsa . . . . . . . . . . . . . . . . . . . . . . . . 23		8.2.2. dcsa . . . . . . . . . . . . . . . . . . . . . . . . 22
	8.3. New Usage Level . . . . . . . . . . . . . . . . . . . . . 23		8.3. New Usage Level . . . . . . . . . . . . . . . . . . . . . 22
	9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24		9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 23
	10. CHANGE LOG . . . . . . . . . . . . . . . . . . . . . . . . . 24		10. CHANGE LOG . . . . . . . . . . . . . . . . . . . . . . . . . 23
	10.1. Changes against 'draft-ietf-mmusic-data-channel-		10.1. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-10' . . . . . . . . . . . . . . . . . . . . . . . 24		sdpneg-11' . . . . . . . . . . . . . . . . . . . . . . . 23
	10.2. Changes against 'draft-ietf-mmusic-data-channel-		10.2. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-09' . . . . . . . . . . . . . . . . . . . . . . . 24		sdpneg-10' . . . . . . . . . . . . . . . . . . . . . . . 23
	10.3. Changes against 'draft-ietf-mmusic-data-channel-		10.3. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-08' . . . . . . . . . . . . . . . . . . . . . . . 25		sdpneg-09' . . . . . . . . . . . . . . . . . . . . . . . 23
	10.4. Changes against 'draft-ietf-mmusic-data-channel-		10.4. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-07' . . . . . . . . . . . . . . . . . . . . . . . 25		sdpneg-08' . . . . . . . . . . . . . . . . . . . . . . . 24
	10.5. Changes against 'draft-ietf-mmusic-data-channel-		10.5. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-06' . . . . . . . . . . . . . . . . . . . . . . . 26		sdpneg-07' . . . . . . . . . . . . . . . . . . . . . . . 25
	10.6. Changes against 'draft-ietf-mmusic-data-channel-		10.6. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-05' . . . . . . . . . . . . . . . . . . . . . . . 26		sdpneg-06' . . . . . . . . . . . . . . . . . . . . . . . 25
	10.7. Changes against 'draft-ietf-mmusic-data-channel-		10.7. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-04' . . . . . . . . . . . . . . . . . . . . . . . 27		sdpneg-05' . . . . . . . . . . . . . . . . . . . . . . . 25
	10.8. Changes against 'draft-ietf-mmusic-data-channel-		10.8. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-03' . . . . . . . . . . . . . . . . . . . . . . . 27		sdpneg-04' . . . . . . . . . . . . . . . . . . . . . . . 26
	10.9. Changes against 'draft-ietf-mmusic-data-channel-		10.9. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 29		sdpneg-03' . . . . . . . . . . . . . . . . . . . . . . . 27
	10.10. Changes against 'draft-ietf-mmusic-data-channel-		10.10. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-01' . . . . . . . . . . . . . . . . . . . . . . . 30		sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 28
	10.11. Changes against 'draft-ietf-mmusic-data-channel-		10.11. Changes against 'draft-ietf-mmusic-data-channel-

	sdpneg-00' . . . . . . . . . . . . . . . . . . . . . . . 32		sdpneg-01' . . . . . . . . . . . . . . . . . . . . . . . 29
	10.12. Changes against 'draft-ejzak-mmusic-data-channel-		10.12. Changes against 'draft-ietf-mmusic-data-channel-
	sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 35		sdpneg-00' . . . . . . . . . . . . . . . . . . . . . . . 31
	10.13. Changes against '-01' . . . . . . . . . . . . . . . . . 36		10.13. Changes against 'draft-ejzak-mmusic-data-channel-
	10.14. Changes against '-00' . . . . . . . . . . . . . . . . . 36		sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 34
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . 36		10.14. Changes against '-01' . . . . . . . . . . . . . . . . . 35
	11.1. Normative References . . . . . . . . . . . . . . . . . . 36		10.15. Changes against '-00' . . . . . . . . . . . . . . . . . 35
	11.2. Informative References . . . . . . . . . . . . . . . . . 37		11. References . . . . . . . . . . . . . . . . . . . . . . . . . 35
			11.1. Normative References . . . . . . . . . . . . . . . . . . 35
			11.2. Informative References . . . . . . . . . . . . . . . . . 36
	Appendix A. Generic Data Channel Negotiation Aspects When Not		Appendix A. Generic Data Channel Negotiation Aspects When Not

	Using DCEP . . . . . . . . . . . . . . . . . . . . . 38		Using DCEP . . . . . . . . . . . . . . . . . . . . . 37
	A.1. Stream Identifier Numbering . . . . . . . . . . . . . . . 39		A.1. Stream Identifier Numbering . . . . . . . . . . . . . . . 38
	A.2. Generic Data Channel Negotiation Not Using DCEP . . . . . 39		A.2. Generic Data Channel Negotiation Not Using DCEP . . . . . 38
	A.2.1. Overview . . . . . . . . . . . . . . . . . . . . . . 39		A.2.1. Overview . . . . . . . . . . . . . . . . . . . . . . 38
	A.2.2. Opening a Data Channel . . . . . . . . . . . . . . . 39		A.2.2. Opening a Data Channel . . . . . . . . . . . . . . . 39
	A.2.3. Closing a Data Channel . . . . . . . . . . . . . . . 40		A.2.3. Closing a Data Channel . . . . . . . . . . . . . . . 40

	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40

	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 the Stream Control Transmission		data channels running on top of the Stream Control Transmission
	Protocol (SCTP). RTCWeb allows applications to use data channels.		Protocol (SCTP). RTCWeb allows applications to use data channels.
	RTCWeb defines an in-band Data Channel Establishment Protocol (DCEP),		RTCWeb defines an in-band Data Channel Establishment Protocol (DCEP),
	however other in-band or out-of-band protocols may be used for		however other in-band or out-of-band protocols may be used for
	establishing data channels. Each data channel consists of paired		establishing data channels. Each data channel consists of paired
	SCTP streams sharing the same SCTP Stream Identifier. Data channels		SCTP streams sharing the same SCTP Stream Identifier. Data channels

	skipping to change at page 4, line 32 ¶		skipping to change at page 4, line 32 ¶
	data channel, and whether it is signaled in-band using DCEP or out-		data channel, and whether it is signaled in-band using DCEP or out-
	of-band using a non-DCEP protocol (or both). In particular, the SDP		of-band using a non-DCEP protocol (or both). In particular, the SDP
	offer generated by the RTCweb data channel stack includes no channel-		offer generated by the RTCweb data channel stack includes no channel-
	specific information.		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 subprotocols,		establish data channels for transport of well-defined subprotocols,
	to enable out-of-band negotiation. These procedures are based on		to enable out-of-band negotiation. These procedures are based on
	generic SDP offer/answer negotiation rules for SCTP based media		generic SDP offer/answer negotiation rules for SCTP based media
	transport as specified in [I-D.ietf-mmusic-sctp-sdp] for the SDP "m"		transport as specified in [I-D.ietf-mmusic-sctp-sdp] for the SDP "m"

	line proto values UDP/DTLS/SCTP and TCP/DTLS/SCTP. In future data		line proto values UDP/DTLS/SCTP and TCP/DTLS/SCTP. In the future,
	channels could be defined over other SCTP based protocols, such as		data channels could be defined over other SCTP based protocols, such
	SCTP over IP. However, corresponding potential other "m" line proto		as SCTP over IP. However, corresponding potential other "m" line
	values are not considered in this document.		proto values are not considered in this document.


	This document makes use of MSRP (Message Session Relay Protocol) in		This document makes use of MSRP (Message Session Relay Protocol) and
	many of the examples. It does not provide a complete specification		BFCP (Binary Floor Control Protocol) in many of the examples. It
	of how to negotiate the use of a data channel to transport MSRP.		does not provide a complete specification of how to negotiate the use
	Procedures specific to each subprotocol such as MSRP are documented		of a data channel to transport MSRP. Procedures specific to each
	elsewhere. The use of MSRP in some examples is only to show how the		subprotocol such as MSRP are documented elsewhere. The use of MSRP
	generic procedures described herein might apply to a specific		in some examples is only to show how the generic procedures described
	subprotocol.		herein might apply to a specific subprotocol.

	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:

	Data channel: A WebRTC data channel as specified in		Data channel: A WebRTC data channel as specified in
	[I-D.ietf-rtcweb-data-channel].		[I-D.ietf-rtcweb-data-channel].

	Data channel stack: An entity which, upon application request,		Data channel stack: An entity which, upon application request,
	runs the data channel protocol to keep track of states, sending		runs the data channel protocol to keep track of states, sending

	and receive data. If the application is a browser based		and receiving data. If the application is a browser based
	JavaScript application then this stack resides in the browser. If		JavaScript application then this stack resides in the browser. If
	the application is a native application then this stack resides in		the application is a native application then this stack resides in
	the application and is accessible via some sort of APIs.		the application and is accessible via some sort of APIs.

	Data channel properties: Fixed properties assigned to a data		Data channel properties: Fixed properties assigned to a data
	channel at the time of its creation. Some of these properties		channel at the time of its creation. Some of these properties
	determine the way the data channel stack transmits data on this		determine the way the data channel stack transmits data on this
	channel (e.g., stream identifier, reliability, order of		channel (e.g., stream identifier, reliability, order of
	delivery...).		delivery...).


	skipping to change at page 7, line 29 ¶		skipping to change at page 7, line 29 ¶

	Syntax:		Syntax:

	dcmap-value = dcmap-stream-id		dcmap-value = dcmap-stream-id
	[ SP dcmap-opt *(";" dcmap-opt) ]		[ SP dcmap-opt *(";" dcmap-opt) ]
	dcmap-opt = ordering-opt / subprotocol-opt / label-opt		dcmap-opt = ordering-opt / subprotocol-opt / label-opt
	/ maxretr-opt / maxtime-opt / priority-opt		/ maxretr-opt / maxtime-opt / priority-opt
	; Either only maxretr-opt or maxtime-opt		; Either only maxretr-opt or maxtime-opt
	; is present.		; is present.


	dcmap-stream-id = 1*DIGIT		dcmap-stream-id = 1*5DIGIT
	ordering-opt = "ordered=" ordering-value		ordering-opt = "ordered=" ordering-value
	ordering-value = "true" / "false"		ordering-value = "true" / "false"
	subprotocol-opt = "subprotocol=" quoted-string		subprotocol-opt = "subprotocol=" quoted-string
	label-opt = "label=" quoted-string		label-opt = "label=" quoted-string
	maxretr-opt = "max-retr=" maxretr-value		maxretr-opt = "max-retr=" maxretr-value
	maxretr-value = "0" / integer		maxretr-value = "0" / integer
	; number of retransmissions,		; number of retransmissions,
	; less than 2^32,		; less than 2^32,
	; derived from 'Reliability Parameter' of		; derived from 'Reliability Parameter' of
	; [I-D.ietf-rtcweb-data-protocol]		; [I-D.ietf-rtcweb-data-protocol]

	skipping to change at page 8, line 7 ¶		skipping to change at page 8, line 7 ¶
	priority-opt = "priority=" priority-value		priority-opt = "priority=" priority-value
	priority-value = "0" / integer		priority-value = "0" / integer
	; unsigned integer value indicating the priority of		; unsigned integer value indicating the priority of
	; the data channel,		; the data channel,
	; less than 2^16,		; less than 2^16,
	; derived from 'Priority' of		; derived from 'Priority' of
	; [I-D.ietf-rtcweb-data-protocol]		; [I-D.ietf-rtcweb-data-protocol]

	quoted-string = DQUOTE *(quoted-char / escaped-char) DQUOTE		quoted-string = DQUOTE *(quoted-char / escaped-char) DQUOTE
	quoted-char = SP / quoted-visible		quoted-char = SP / quoted-visible

	quoted-visible = %21 / %23-24 / %26-7E ; VCHAR without " or %		quoted-visible = %x21 / %x23-24 / %x26-7E ; VCHAR without " or %
	escaped-char = "%" HEXDIG HEXDIG		escaped-char = "%" HEXDIG HEXDIG
	DQUOTE = <from-RFC5234>		DQUOTE = <from-RFC5234>
	integer = <from-RFC4566>		integer = <from-RFC4566>

	Examples:		Examples:

	a=dcmap:0		a=dcmap:0
	a=dcmap:1 subprotocol="BFCP";max-time=60000;priority=512		a=dcmap:1 subprotocol="BFCP";max-time=60000;priority=512
	a=dcmap:2 subprotocol="MSRP";ordered=true;label="MSRP"		a=dcmap:2 subprotocol="MSRP";ordered=true;label="MSRP"
	a=dcmap:3 label="Label 1";ordered=false;max-retr=5;priority=128		a=dcmap:3 label="Label 1";ordered=false;max-retr=5;priority=128

	skipping to change at page 11, line 23 ¶		skipping to change at page 11, line 23 ¶

	Usage Level: media		Usage Level: media

	Charset Dependent: no		Charset Dependent: no

	Syntax:		Syntax:

	dcsa-value = stream-id SP attribute		dcsa-value = stream-id SP attribute
	attribute = <from-RFC4566>		attribute = <from-RFC4566>


	Example:		Example (other MSRP related SDP attributes are omitted for brevity):

	a=dcsa:2 accept-types:text/plain		a=dcsa:2 accept-types:text/plain

	Note that the above reference to [RFC4566] defines where the		Note that the above reference to [RFC4566] defines where the
	attribute definition can be found; it does not provide any limitation		attribute definition can be found; it does not provide any limitation
	on support of attributes defined in other documents in accordance		on support of attributes defined in other documents in accordance
	with this attribute definition. Note however that not all SDP		with this attribute definition. Note however that not all SDP
	attributes are suitable as a "a=dcsa:" parameter.		attributes are suitable as a "a=dcsa:" parameter.
	[IANA-SDP-Parameters] contains the lists of IANA (Internet Assigned		[IANA-SDP-Parameters] contains the lists of IANA (Internet Assigned
	Numbers Authority) registered session and media level or media level		Numbers Authority) registered session and media level or media level

	skipping to change at page 12, line 10 ¶		skipping to change at page 12, line 10 ¶
	attributes are used in the same way as defined in the original		attributes are used in the same way as defined in the original
	subprotocol specification, also if the subprotocol is transported		subprotocol specification, also if the subprotocol is transported
	over a data channel and if the attribute is correspondingly embedded		over a data channel and if the attribute is correspondingly embedded
	in a "a=dcsa" attribute.		in a "a=dcsa" attribute.

	There may be cases, where the usage of a subprotocol related media		There may be cases, where the usage of a subprotocol related media
	level attribute depends on the subprotocol's transport protocol. In		level attribute depends on the subprotocol's transport protocol. In
	such cases the subprotocol related usage of the attribute is expected		such cases the subprotocol related usage of the attribute is expected
	to be described for the data channel transport. A data channel		to be described for the data channel transport. A data channel
	specific usage of a subprotocol attribute is expected to be specified		specific usage of a subprotocol attribute is expected to be specified

	in the same document, which registers the subprotocol's identifier		in the same document, that registers the subprotocol's identifier for
	for data channel usage as described in Section 8.1.		data channel usage as described in Section 8.1.

	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.

	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
	association is outside the scope of [I-D.ietf-mmusic-sctp-sdp], no		association is outside the scope of [I-D.ietf-mmusic-sctp-sdp], no
	"a=dcsa:" attribute multiplexing rules are specified for the		"a=dcsa:" attribute multiplexing rules are specified for the
	UDP/DTLS/SCTP and TCP/DTLS/SCTP proto values. If future extensions		UDP/DTLS/SCTP and TCP/DTLS/SCTP proto values. If future extensions
	of [I-D.ietf-mmusic-sctp-sdp] define how to negotiate multiplexing of		of [I-D.ietf-mmusic-sctp-sdp] define how to negotiate multiplexing of

	skipping to change at page 13, line 21 ¶		skipping to change at page 13, line 21 ¶
	5.2.2. Negotiating Data Channel Parameters		5.2.2. Negotiating Data Channel Parameters

	Conveying a reliable data channel is achieved by including neither		Conveying a reliable data channel is achieved by including neither
	'max-retr' nor 'max-time' in corresponding SDP offer's or answer's		'max-retr' nor 'max-time' in corresponding SDP offer's or answer's
	"a=dcmap:" attribute line. Conveying a partially reliable data		"a=dcmap:" attribute line. Conveying a partially reliable data
	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 a SDP offer contains both of these parameters then the		line. If a SDP offer contains both of these parameters then the
	receiver of such an SDP offer MUST reject the SDP offer. If a SDP		receiver of such an SDP offer MUST reject the SDP offer. If a SDP

	answer contains both of these parameters then the offerer MAY treat		answer contains both of these parameters then the offerer MUST treat
	it as an error and MAY assume the associated SDP offer/answer failed		the associated SDP offer/answer failed and take appropriate recovery
	and MAY take appropriate recovery actions. These recovery options		actions. These recovery options are outside the scope of this
	are outside the scope of this document.		document.

	The SDP answer SHALL echo the same subprotocol, max-retr, max-time,		The SDP answer SHALL echo the same subprotocol, 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.


	skipping to change at page 15, line 13 ¶		skipping to change at page 15, line 13 ¶
	o Sends the SDP offer.		o Sends the SDP offer.

	The peer receiving such an SDP offer performs the following:		The peer receiving such an SDP offer performs the following:

	o Parses and applies the SDP offer, taking into account the		o Parses and applies the SDP offer, taking into account the
	considerations discussed in Section 5.2.5.		considerations discussed in Section 5.2.5.

	o Analyzes the channel parameters and subprotocol attributes to		o Analyzes the channel parameters and subprotocol attributes to
	determine whether to accept each offered data channel.		determine whether to accept each offered data channel.


	o For accepted data channels, it creates peer instances for the data		o For accepted data channels, the agent MUST create peer instances
	channels with the agent using the channel parameters described in		for the data channels using the SCTP stream identifiers and
	the SDP offer. Note that the agent is asked to create data		channel parameters contained in the SDP offer.
	channels with SCTP stream identifiers contained in the SDP offer
	if the SDP offer is accepted.

	o Generates an SDP answer.		o Generates an SDP answer.

	o Completes the SDP answer with the "a=dcmap:" and optional		o Completes the SDP answer with the "a=dcmap:" and optional
	"a=dcsa:" attributes needed for each SDP offer/answer negotiated		"a=dcsa:" attributes needed for each SDP offer/answer negotiated
	data channel, as described in Section 5.1 and in Section 5.2.2.		data channel, as described in Section 5.1 and in Section 5.2.2.

	o Sends the SDP answer.		o Sends the SDP answer.

	The agent receiving such an SDP answer performs the following:		The agent receiving such an SDP answer performs the following:

	skipping to change at page 16, line 33 ¶		skipping to change at page 16, line 31 ¶
	(unless all data channels are being closed and the SCTP association		(unless all data channels are being closed and the SCTP association
	is no longer needed), since this would close the SCTP association and		is no longer needed), since this would close the SCTP association and
	impact all of the data channels. If the answerer accepts the SDP		impact all of the data channels. If the answerer accepts the SDP
	offer then the answerer MUST close those data channels whose		offer then the answerer MUST close those data channels whose
	"a=dcmap:" and "a=dcsa:" attribute lines were excluded from the		"a=dcmap:" and "a=dcsa:" attribute lines were excluded from the
	received SDP offer, unless those data channels were already closed,		received SDP offer, unless those data channels were already closed,
	and the answerer MUST also exclude the corresponding attribute lines		and the answerer MUST also exclude the corresponding attribute lines
	in the answer. In addition to that, the SDP answerer MAY exclude		in the answer. In addition to that, the SDP answerer MAY exclude
	other data channels which were closed but not yet communicated to the		other data channels which were closed but not yet communicated to the
	peer. So, the offerer MUST inspect the answer to see if it has to		peer. So, the offerer MUST inspect the answer to see if it has to

	close other data channels which are now not included in the answer.		close other data channels that are now not included in the answer.

	If a new SDP offer/answer is used to close data channels then the		If a new SDP offer/answer is used to close data channels then the
	data channel(s) SHOULD only be closed by the answerer/offerer after a		data channel(s) SHOULD only be closed by the answerer/offerer after a
	successful SDP answer is sent/received.		successful SDP answer is sent/received.

	This delayed closure is RECOMMENDED in order to handle cases where		This delayed closure is RECOMMENDED in order to handle cases where
	a successful SDP answer is not received, in which case the state		a successful SDP answer is not received, in which case the state
	of the session SHOULD be kept per the last successful SDP offer/		of the session SHOULD be kept per the last successful SDP offer/
	answer.		answer.


	skipping to change at page 17, line 24 ¶		skipping to change at page 17, line 21 ¶

	5.2.5. Various SDP Offer/Answer Scenarios and Considerations		5.2.5. Various SDP Offer/Answer Scenarios and Considerations

	SDP offer has no "a=dcmap:" attributes.		SDP offer has no "a=dcmap:" attributes.

	* Initial SDP offer: No data channel is negotiated yet. The DTLS		* Initial SDP offer: No data channel is negotiated yet. The DTLS
	association and SCTP association is negotiated and, if agreed,		association and SCTP association is negotiated and, if agreed,
	established as per [I-D.ietf-mmusic-sctp-sdp].		established as per [I-D.ietf-mmusic-sctp-sdp].

	* Subsequent SDP offer: All the SDP offer/answer negotiated data		* Subsequent SDP offer: All the SDP offer/answer negotiated data

	channels are expected be closed now. The DTLS/SCTP association		channels are expected to be closed now. The DTLS/SCTP
	remains open for SDP offer/answer or DCEP negotiation of data		association remains open for SDP offer/answer or DCEP
	channels.		negotiation of data channels.

	SDP answer has no "a=dcmap:" attributes.		SDP answer has no "a=dcmap:" attributes.

	* Initial SDP answer: Either the peer does not support "a=dcmap:"		* Initial SDP answer: Either the peer does not support "a=dcmap:"
	attributes or it rejected all the data channels. In either		attributes or it rejected all the data channels. In either
	case the offerer closes all the SDP offer/answer negotiated		case the offerer closes all the SDP offer/answer negotiated
	data channels that were open at the time of initial offer. The		data channels that were open at the time of initial offer. The
	DTLS association and SCTP association will still be setup.		DTLS association and SCTP association will still be setup.

	* Subsequent SDP answer: All the SDP offer/answer negotiated data		* Subsequent SDP answer: All the SDP offer/answer negotiated data

	channels are expected be closed now. The SCTP association		channels are expected to be closed now. The SCTP association
	remains open for future SDP offer/answer or DCEP negotiation of		remains open for future SDP offer/answer or DCEP negotiation of
	data channels.		data channels.

	SDP offer or answer has no "a=dcmap:" attributes but has "a=dcsa:"		SDP offer or answer has no "a=dcmap:" attributes but has "a=dcsa:"
	attributes.		attributes.

	* This is considered an error case. In this case the receiver of		* This is considered an error case. In this case the receiver of
	such an SDP offer or answer SHOULD ignore the "a=dcsa:"		such an SDP offer or answer SHOULD ignore the "a=dcsa:"
	attributes and SHOULD process the SDP offer or answer as per		attributes and SHOULD process the SDP offer or answer as per
	above case 'SDP offer has no "a=dcmap:" attributes' or case		above case 'SDP offer has no "a=dcmap:" attributes' or case

	skipping to change at page 19, line 4 ¶		skipping to change at page 18, line 26 ¶
	entire "a=dcsa" attribute line.		entire "a=dcsa" attribute line.

	SDP offer or answer has an "a=dcsa" attribute, whose subprotocol		SDP offer or answer has an "a=dcsa" attribute, whose subprotocol
	attribute is known, but whose subprotocol attribute semantic is		attribute is known, but whose subprotocol attribute semantic is
	not known for the data channel transport case.		not known for the data channel transport case.

	* The receiver of such an SDP offer or answer SHOULD ignore this		* The receiver of such an SDP offer or answer SHOULD ignore this
	entire "a=dcsa" attribute line.		entire "a=dcsa" attribute line.

	6. Examples		6. Examples


	SDP offer:		SDP offer:

	m=application 10001 UDP/DTLS/SCTP webrtc-datachannel		m=application 10001 UDP/DTLS/SCTP webrtc-datachannel

	c=IN IP4 10.10.10.1		c=IN IP4 192.0.2.1
	a=max-message-size:100000		a=max-message-size:100000
	a=sctp-port:5000		a=sctp-port:5000
	a=setup:actpass		a=setup:actpass
	a=fingerprint:SHA-1 \		a=fingerprint:SHA-1 \
	4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB		4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB
	a=dtls-id:4a7565		a=dtls-id:4a7565
	a=dcmap:0 subprotocol="BFCP";label="BFCP"		a=dcmap:0 subprotocol="BFCP";label="BFCP"

	SDP answer:		SDP answer:

	m=application 10002 UDP/DTLS/SCTP webrtc-datachannel		m=application 10002 UDP/DTLS/SCTP webrtc-datachannel

	c=IN IP4 10.10.10.2		c=IN IP4 192.0.2.2
	a=max-message-size:100000		a=max-message-size:100000
	a=sctp-port:5002		a=sctp-port:5002
	a=setup:passive		a=setup:passive
	a=fingerprint:SHA-1 \		a=fingerprint:SHA-1 \
	5B:AD:67:B1:3E:82:AC:3B:90:02:B1:DF:12:5D:CA:6B:3F:E5:54:FA		5B:AD:67:B1:3E:82:AC:3B:90:02:B1:DF:12:5D:CA:6B:3F:E5:54:FA
	a=dtls-id:532d42		a=dtls-id:532d42

	Figure 1: Example 1		Figure 1: Example 1

	In the above example the SDP answerer rejected the data channel with		In the above example the SDP answerer rejected the data channel with
	stream id 0 either for explicit reasons or because it does not		stream id 0 either for explicit reasons or because it does not
	understand the "a=dcmap:" attribute. As a result the offerer will		understand the "a=dcmap:" attribute. As a result the offerer will
	close the data channel created with the SDP offer/answer negotiation		close the data channel created with the SDP offer/answer negotiation
	option. The SCTP association will still be setup over DTLS. At this		option. The SCTP association will still be setup over DTLS. At this
	point the offerer or the answerer may use DCEP negotiation to open		point the offerer or the answerer may use DCEP negotiation to open
	data channels.		data channels.

	SDP offer:		SDP offer:

	m=application 10001 UDP/DTLS/SCTP webrtc-datachannel		m=application 10001 UDP/DTLS/SCTP webrtc-datachannel

	c=IN IP4 10.10.10.1		c=IN IP4 192.0.2.1
	a=max-message-size:100000		a=max-message-size:100000
	a=sctp-port:5000		a=sctp-port:5000
	a=setup:actpass		a=setup:actpass
	a=fingerprint:SHA-1 \		a=fingerprint:SHA-1 \
	4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB		4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB
	a=dtls-id:4a7565		a=dtls-id:4a7565
	a=dcmap:0 subprotocol="BFCP";label="BFCP"		a=dcmap:0 subprotocol="BFCP";label="BFCP"
	a=dcmap:2 subprotocol="MSRP";label="MSRP"		a=dcmap:2 subprotocol="MSRP";label="MSRP"
	a=dcsa:2 accept-types:message/cpim text/plain		a=dcsa:2 accept-types:message/cpim text/plain
	a=dcsa:2 path:msrp://alice.example.com:10001/2s93i93idj;dc		a=dcsa:2 path:msrp://alice.example.com:10001/2s93i93idj;dc

	SDP answer:		SDP answer:

	m=application 10002 UDP/DTLS/SCTP webrtc-datachannel		m=application 10002 UDP/DTLS/SCTP webrtc-datachannel

	c=IN IP4 10.10.10.2		c=IN IP4 192.0.2.2
	a=max-message-size:100000		a=max-message-size:100000
	a=sctp-port:5002		a=sctp-port:5002
	a=setup:passive		a=setup:passive
	a=fingerprint:SHA-1 \		a=fingerprint:SHA-1 \
	5B:AD:67:B1:3E:82:AC:3B:90:02:B1:DF:12:5D:CA:6B:3F:E5:54:FA		5B:AD:67:B1:3E:82:AC:3B:90:02:B1:DF:12:5D:CA:6B:3F:E5:54:FA
	a=dtls-id:532d42		a=dtls-id:532d42
	a=dcmap:2 subprotocol="MSRP";label="MSRP"		a=dcmap:2 subprotocol="MSRP";label="MSRP"
	a=dcsa:2 accept-types:message/cpim text/plain		a=dcsa:2 accept-types:message/cpim text/plain
	a=dcsa:2 path:msrp://bob.example.com:10002/si438dsaodes;dc		a=dcsa:2 path:msrp://bob.example.com:10002/si438dsaodes;dc


	skipping to change at page 21, line 8 ¶		skipping to change at page 20, line 8 ¶
	data channel for BFCP and both offerer and answerer may start using		data channel for BFCP and both offerer and answerer may start using
	the MSRP data channel (after the SCTP association is set up). The		the MSRP data channel (after the SCTP association is set up). The
	data channel with stream id 0 is free and can be used for future DCEP		data channel with stream id 0 is free and can be used for future DCEP
	or SDP offer/answer negotiation.		or SDP offer/answer negotiation.

	Continuing the example in Figure 2.		Continuing the example in Figure 2.

	Subsequent SDP offer:		Subsequent SDP offer:

	m=application 10001 UDP/DTLS/SCTP webrtc-datachannel		m=application 10001 UDP/DTLS/SCTP webrtc-datachannel

	c=IN IP4 10.10.10.1		c=IN IP4 192.0.2.1
	a=max-message-size:100000		a=max-message-size:100000
	a=sctp-port:5000		a=sctp-port:5000
	a=setup:actpass		a=setup:actpass
	a=fingerprint:SHA-1 \		a=fingerprint:SHA-1 \
	4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB		4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB
	a=dtls-id:4a7565		a=dtls-id:4a7565
	a=dcmap:4 subprotocol="MSRP";label="MSRP"		a=dcmap:4 subprotocol="MSRP";label="MSRP"
	a=dcsa:4 accept-types:message/cpim text/plain		a=dcsa:4 accept-types:message/cpim text/plain
	a=dcsa:4 path:msrp://alice.example.com:10001/2s93i93idj;dc		a=dcsa:4 path:msrp://alice.example.com:10001/2s93i93idj;dc

	Subsequent SDP answer:		Subsequent SDP answer:

	m=application 10002 UDP/DTLS/SCTP webrtc-datachannel		m=application 10002 UDP/DTLS/SCTP webrtc-datachannel

	c=IN IP4 10.10.10.2		c=IN IP4 192.0.2.2
	a=max-message-size:100000		a=max-message-size:100000
	a=sctp-port:5002		a=sctp-port:5002
	a=setup:passive		a=setup:passive
	a=fingerprint:SHA-1 \		a=fingerprint:SHA-1 \
	5B:AD:67:B1:3E:82:AC:3B:90:02:B1:DF:12:5D:CA:6B:3F:E5:54:FA		5B:AD:67:B1:3E:82:AC:3B:90:02:B1:DF:12:5D:CA:6B:3F:E5:54:FA
	a=dtls-id:532d42		a=dtls-id:532d42
	a=dcmap:4 subprotocol="MSRP";label="MSRP"		a=dcmap:4 subprotocol="MSRP";label="MSRP"
	a=dcsa:4 accept-types:message/cpim text/plain		a=dcsa:4 accept-types:message/cpim text/plain
	a=dcsa:4 path:msrp://bob.example.com:10002/si438dsaodes;dc		a=dcsa:4 path:msrp://bob.example.com:10002/si438dsaodes;dc


	skipping to change at page 23, line 49 ¶		skipping to change at page 22, line 49 ¶
	\| O/A procedures: \| As per Section 5.2 \|		\| O/A procedures: \| As per Section 5.2 \|
	\| Mux category: \| SPECIAL. See Section 5.1.2.2 \|		\| Mux category: \| SPECIAL. See Section 5.1.2.2 \|
	\| Reference: \| RFCXXXX \|		\| Reference: \| RFCXXXX \|
	+-----------------------+-------------------------------------------+		+-----------------------+-------------------------------------------+

	8.3. New Usage Level		8.3. New Usage Level

	This document introduces a new "Data Channel Subprotocol Attribute"		This document introduces a new "Data Channel Subprotocol Attribute"
	(dcsa) usage level to the SDP to the IANA SDP att-field registry.		(dcsa) usage level to the SDP to the IANA SDP att-field registry.
	SDP attributes that are defined for use at the dcsa usage level only		SDP attributes that are defined for use at the dcsa usage level only

	shall use the dcsa usage level when registering the attribute. If		SHALL use the dcsa usage level when registering the attribute. If
	existing media attributes are used in a datachannel subprotocol		existing media attributes are used in a datachannel subprotocol
	specific way (Section 5.1.2.1), then a new dcsa usage level MUST be		specific way (Section 5.1.2.1), then a new dcsa usage level MUST be
	defined for the existing media attribute. Where the SDP attribute is		defined for the existing media attribute. Where the SDP attribute is
	applicable to a particular subprotocol/s this SHALL also be		applicable to a particular subprotocol/s this SHALL also be
	registered by indicating the applicable subprotocol identifiers (see		registered by indicating the applicable subprotocol identifiers (see
	Section 8.1) along with the dcsa usage level. E.g.		Section 8.1) along with the dcsa usage level. E.g.

	+-----------------------+-------------------------------------------+		+-----------------------+-------------------------------------------+
	\| ... \| ... \|		\| ... \| ... \|
	\| Usage level: \| dcsa(MSRP) \|		\| Usage level: \| dcsa(MSRP) \|

	skipping to change at page 24, line 25 ¶		skipping to change at page 23, line 25 ¶

	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 Flemming Andreasen, Roni Even,		and Gavin Llewellyn, and to thank Flemming Andreasen, Roni Even,
	Christian Groves, Gunnar Hellstrom, Christer Holmberg, Paul Kyzivat,		Christian Groves, Gunnar Hellstrom, Christer Holmberg, Paul Kyzivat,
	Jonathan Lennox, Uwe Rauschenbach and Roman Shpount for their		Jonathan Lennox, Uwe Rauschenbach and Roman Shpount for their
	invaluable comments.		invaluable comments.

	10. CHANGE LOG		10. CHANGE LOG


	10.1. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-10'		10.1. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-11'

			o dcmap-stream-id syntax change to limit size to 5 digits.

			o Add missing 'x' prefix to quoted-visible syntax.

			o Align SDP offerer and answerer handling when both max-retr and
			max-time are present.

			o Use of TEST-NET-1 ip addresses in examples.

			o Add missing a=dtls-id in one example.

			10.2. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-10'

	o Removal of the "a=connection" attribute lines from all SDP		o Removal of the "a=connection" attribute lines from all SDP
	examples.		examples.


	10.2. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-09'		10.3. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-09'

	o In the introduction:		o In the introduction:

	* Replacement of the sentence "The RTCWeb working group has		* Replacement of the sentence "The RTCWeb working group has
	defined the concept of bi-directional data channels running on		defined the concept of bi-directional data channels running on
	top of SCTP/DTLS (SCTP over the Datagram Transport Layer		top of SCTP/DTLS (SCTP over the Datagram Transport Layer
	Security protocol)" with "The RTCWeb working group has defined		Security protocol)" with "The RTCWeb working group has defined
	the concept of bi-directional data channels running on top of		the concept of bi-directional data channels running on top of
	the Stream Control Transmission Protocol (SCTP)".		the Stream Control Transmission Protocol (SCTP)".

	* Addition of following sentences to the second paragraph: "These		* Addition of following sentences to the second paragraph: "These
	procedures are based on generic SDP offer/answer negotiation		procedures are based on generic SDP offer/answer negotiation
	rules for SCTP based media transport as specified in		rules for SCTP based media transport as specified in
	[I-D.ietf-mmusic-sctp-sdp] for the SDP "m" line proto values		[I-D.ietf-mmusic-sctp-sdp] for the SDP "m" line proto values

	UDP/DTLS/SCTP and TCP/DTLS/SCTP. In future data channels could		UDP/DTLS/SCTP and TCP/DTLS/SCTP. In the future, data channels
	be defined over other SCTP based protocols, such as SCTP over		could be defined over other SCTP based protocols, such as SCTP
	IP. However, corresponding potential other "m" line proto		over IP. However, corresponding potential other "m" line proto
	values are not considered in this document."		values are not considered in this document."

	o Replacement of "DTLS connection" with "DTLS association"		o Replacement of "DTLS connection" with "DTLS association"
	throughout the document.		throughout the document.

	o In sections Section 5.1.1.2 and Section 5.1.2.2 removal of the		o In sections Section 5.1.1.2 and Section 5.1.2.2 removal of the
	sentences "This document also does not specify multiplexing rules		sentences "This document also does not specify multiplexing rules
	for this attribute for SCTP or SCTP/DTLS proto values".		for this attribute for SCTP or SCTP/DTLS proto values".

	o In the text related to "Subsequent SDP answer" in section		o In the text related to "Subsequent SDP answer" in section

	skipping to change at page 25, line 23 ¶		skipping to change at page 24, line 37 ¶
	o In the text after the second SDP answer in section Section 6		o In the text after the second SDP answer in section Section 6
	replacement of "... (after SCTP/DTLS association is setup)" with		replacement of "... (after SCTP/DTLS association is setup)" with
	"... (after the SCTP association is set up)".		"... (after the SCTP association is set up)".

	o Addition of [I-D.ietf-mmusic-dtls-sdp] to the list of informative		o Addition of [I-D.ietf-mmusic-dtls-sdp] to the list of informative
	references.		references.

	o Addition of "a=dtls-id" attribute lines to the SDP offer/answer		o Addition of "a=dtls-id" attribute lines to the SDP offer/answer
	examples in Section 6.		examples in Section 6.


	10.3. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-08'		10.4. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-08'

	o Addition of definition of "data channel subprotocol" to Section 3		o Addition of definition of "data channel subprotocol" to Section 3
	as proposed on the MMUSIC list, https://www.ietf.org/mail-		as proposed on the MMUSIC list, https://www.ietf.org/mail-
	archive/web/mmusic/current/msg15827.html.		archive/web/mmusic/current/msg15827.html.

	o Addition of [I-D.ietf-mmusic-rfc4566bis] to list of normative		o Addition of [I-D.ietf-mmusic-rfc4566bis] to list of normative
	references.		references.

	o Updates of tables in Section 8.2.1 and Section 8.2.2 as per		o Updates of tables in Section 8.2.1 and Section 8.2.2 as per
	section 8.2.4 of [I-D.ietf-mmusic-rfc4566bis].		section 8.2.4 of [I-D.ietf-mmusic-rfc4566bis].

	o Addition of new Section 8.3.		o Addition of new Section 8.3.


	10.4. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-07'		10.5. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-07'

	o Addition of two new paragraphs to Section 5.1.2.1 regarding		o Addition of two new paragraphs to Section 5.1.2.1 regarding
	subprotocol attribute relationship with transport protocol.		subprotocol attribute relationship with transport protocol.

	o Addition of a note to Section 8.1 regarding subprotocols		o Addition of a note to Section 8.1 regarding subprotocols
	simultaneously defined for data channel and Websocket usage.		simultaneously defined for data channel and Websocket usage.

	o Addition of two further SDP offer/answer considerations to		o Addition of two further SDP offer/answer considerations to
	Section 5.2.5 regarding unknown subprotocol attributes and known		Section 5.2.5 regarding unknown subprotocol attributes and known
	subprotocol attributes with unknown data channel transport related		subprotocol attributes with unknown data channel transport related
	semantic.		semantic.


	10.5. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-06'		10.6. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-06'

	o Changes addressing Christian Groves's WGLC review comments raised		o Changes addressing Christian Groves's WGLC review comments raised
	in http://www.ietf.org/mail-archive/web/mmusic/current/		in http://www.ietf.org/mail-archive/web/mmusic/current/
	msg15357.html and http://www.ietf.org/mail-		msg15357.html and http://www.ietf.org/mail-
	archive/web/mmusic/current/msg15359.html.		archive/web/mmusic/current/msg15359.html.


	10.6. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-05'		10.7. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-05'

	o In IANA registration Section 8.2.1 and Section 8.2.2 replacement		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		of contact name and e-mail address with "MMUSIC Chairs" and
	"mmusic-chairs@ietf.org".		"mmusic-chairs@ietf.org".

	o In Section 5.1.2.1 replacement of "Thus in the example above, the		o In Section 5.1.2.1 replacement of "Thus in the example above, the
	original attribute line "a=accept- types:text/plain" is		original attribute line "a=accept- types:text/plain" is
	represented by the attribute line "a=dcsa:2 accept-types:text/		represented by the attribute line "a=dcsa:2 accept-types:text/
	plain", which specifies that this instance of MSRP being		plain", which specifies that this instance of MSRP being
	transported on the SCTP association using the data channel with		transported on the SCTP association using the data channel with

	skipping to change at page 27, line 5 ¶		skipping to change at page 26, line 14 ¶

	o Move of the last but one paragraph of Section 5.1.2.1 starting		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		with "The same syntax applies to ..." right in front of the formal
	syntax definition of the "dcsa" attribute.		syntax definition of the "dcsa" attribute.

	o Modifications of the text in Section 5.1.1.2 and Section 5.1.2.2		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		in order not to explicitly restrict usage of the "a=dcmap:" and
	"a=dcsa:" attributes to "m" lines with proto values "UDP/DTLS/		"a=dcsa:" attributes to "m" lines with proto values "UDP/DTLS/
	SCTP" or "TCP/DTLS/SCTP".		SCTP" or "TCP/DTLS/SCTP".


	10.7. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-04'		10.8. 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

	skipping to change at page 27, line 46 ¶		skipping to change at page 27, line 8 ¶

	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.


	10.8. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-03'		10.9. 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 29, line 8 ¶		skipping to change at page 28, line 17 ¶
	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.


	10.9. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-02'		10.10. 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 30, line 10 ¶		skipping to change at page 29, line 19 ¶
	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.


	10.10. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-01'		10.11. 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 31, line 11 ¶		skipping to change at page 30, line 22 ¶
	o In Section 5.2.5 the description of bullet point "SDP offer has no		o In Section 5.2.5 the description of bullet point "SDP offer has no
	a=dcmap attributes - Initial SDP offer:" was "Initial SDP offer:		a=dcmap attributes - Initial SDP offer:" was "Initial SDP offer:
	No data channel negotiated yet." Replacement of this description		No data channel negotiated yet." Replacement of this description
	with "Initial SDP offer: No data channel is negotiated yet. The		with "Initial SDP offer: No data channel is negotiated yet. The
	DTLS connection and SCTP association is negotiated and, if agreed,		DTLS connection and SCTP association is negotiated and, if agreed,
	established as per [I-D.ietf-mmusic-sctp-sdp]."		established as per [I-D.ietf-mmusic-sctp-sdp]."

	o In Section 5.2.5 in both bullet points related to "Subsequent SDP		o In Section 5.2.5 in both bullet points related to "Subsequent SDP
	offer" and "Subsequent SDP answer" replacement of "All the		offer" and "Subsequent SDP answer" replacement of "All the
	externally negotiated data channels must be closed now." with "All		externally negotiated data channels must be closed now." with "All

	the externally negotiated data channels are expected be closed		the externally negotiated data channels are expected to be closed
	now.".		now.".

	o In Appendix A.2.2's sixth paragraph beginning with "[ASSUMPTION]"		o In Appendix A.2.2's sixth paragraph beginning with "[ASSUMPTION]"
	replacement of the two occurrences of "must" with "MUST".		replacement of the two occurrences of "must" with "MUST".

	o In Section 5.1.1.1 in the definition of the ABNF rule "dcmap-opt"		o In Section 5.1.1.1 in the definition of the ABNF rule "dcmap-opt"
	there was a comment saying that "Either only maxretr-opt or		there was a comment saying that "Either only maxretr-opt or
	maxtime-opt is present. Both MUST not be present." Removal of		maxtime-opt is present. Both MUST not be present." Removal of
	the second normative sentence and instead addition of following		the second normative sentence and instead addition of following
	new paragraph to the end of this section: "Within an 'a=dcmap'		new paragraph to the end of this section: "Within an 'a=dcmap'

	skipping to change at page 32, line 15 ¶		skipping to change at page 31, line 26 ¶
	* 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."


	10.11. Changes against 'draft-ietf-mmusic-data-channel-sdpneg-00'		10.12. 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 35, line 5 ¶		skipping to change at page 34, line 11 ¶
	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.


	10.12. Changes against 'draft-ejzak-mmusic-data-channel-sdpneg-02'		10.13. 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 36, line 7 ¶		skipping to change at page 35, line 14 ¶

	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.


	10.13. Changes against '-01'		10.14. 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.


	10.14. Changes against '-00'		10.15. 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 37, line 30 ¶		skipping to change at page 36, line 34 ¶
	[I-D.ietf-rtcweb-data-channel]		[I-D.ietf-rtcweb-data-channel]
	Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data		Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data
	Channels", draft-ietf-rtcweb-data-channel-13 (work in		Channels", draft-ietf-rtcweb-data-channel-13 (work in
	progress), January 2015.		progress), January 2015.

	[I-D.ietf-mmusic-sctp-sdp]		[I-D.ietf-mmusic-sctp-sdp]
	Holmberg, C., Shpount, R., Loreto, S., and G. Camarillo,		Holmberg, C., Shpount, R., Loreto, S., and G. Camarillo,
	"Session Description Protocol (SDP) Offer/Answer		"Session Description Protocol (SDP) Offer/Answer
	Procedures For Stream Control Transmission Protocol (SCTP)		Procedures For Stream Control Transmission Protocol (SCTP)
	over Datagram Transport Layer Security (DTLS) Transport.",		over Datagram Transport Layer Security (DTLS) Transport.",

	draft-ietf-mmusic-sctp-sdp-20 (work in progress), December		draft-ietf-mmusic-sctp-sdp-25 (work in progress), March
	2016.		2017.

	[I-D.ietf-mmusic-sdp-mux-attributes]		[I-D.ietf-mmusic-sdp-mux-attributes]
	Nandakumar, S., "A Framework for SDP Attributes when		Nandakumar, S., "A Framework for SDP Attributes when
	Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-16		Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-16
	(work in progress), December 2016.		(work in progress), December 2016.

	11.2. Informative References		11.2. Informative References

	[I-D.ietf-rtcweb-data-protocol]		[I-D.ietf-rtcweb-data-protocol]
	Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel		Jesup, R., Loreto, S., and M. Tuexen, "WebRTC Data Channel
	Establishment Protocol", draft-ietf-rtcweb-data-		Establishment Protocol", draft-ietf-rtcweb-data-
	protocol-09 (work in progress), January 2015.		protocol-09 (work in progress), January 2015.

	[I-D.ietf-mmusic-dtls-sdp]		[I-D.ietf-mmusic-dtls-sdp]
	Holmberg, C. and R. Shpount, "Using the SDP Offer/Answer		Holmberg, C. and R. Shpount, "Using the SDP Offer/Answer

	Mechanism for DTLS", draft-ietf-mmusic-dtls-sdp-15 (work		Mechanism for DTLS", draft-ietf-mmusic-dtls-sdp-22 (work
	in progress), October 2016.		in progress), March 2017.

	[RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol",		[RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol",
	RFC 4960, DOI 10.17487/RFC4960, September 2007,		RFC 4960, DOI 10.17487/RFC4960, September 2007,
	<http://www.rfc-editor.org/info/rfc4960>.		<http://www.rfc-editor.org/info/rfc4960>.

	[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/

	skipping to change at page 38, line 39 ¶		skipping to change at page 37, line 43 ¶
	priority). The application also specifies if it wants to make use of		priority). The application also specifies if it wants to make use of
	the negotiation using the DCEP [I-D.ietf-rtcweb-data-protocol], or if		the negotiation using the DCEP [I-D.ietf-rtcweb-data-protocol], or if
	the application intends to negotiate data channels using the SDP		the application intends to negotiate data channels using the SDP
	offer/answer protocol.		offer/answer protocol.

	In any case, the SDP offer generated by the application is per		In any case, the SDP offer generated by the application is per
	[I-D.ietf-mmusic-sctp-sdp]. In brief, it contains one "m" line for		[I-D.ietf-mmusic-sctp-sdp]. In brief, it contains one "m" line for
	the SCTP association on top of which data channels will run:		the SCTP association on top of which data channels will run:

	m=application 54111 UDP/DTLS/SCTP webrtc-datachannel		m=application 54111 UDP/DTLS/SCTP webrtc-datachannel

	c=IN IP4 79.97.215.79		c=IN IP4 10.10.10.1
	a=max-message-size:100000		a=max-message-size:100000
	a=sctp-port:5000		a=sctp-port:5000

			a=dtls-id:abcdef1234567
	a=setup:actpass		a=setup:actpass
	a=fingerprint:SHA-1 \		a=fingerprint:SHA-1 \
	4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB		4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB

	Note: A WebRTC application will only use "m" line format "webrtc-		Note: A WebRTC application will only use "m" line format "webrtc-
	datachannel", and will not use other formats in the "m" line for		datachannel", and will not use other formats in the "m" line for
	other protocols such as t38. [I-D.ietf-mmusic-sctp-sdp] supports		other protocols such as t38. [I-D.ietf-mmusic-sctp-sdp] supports
	only one SCTP association to be established on top of a DTLS		only one SCTP association to be established on top of a DTLS
	association.		association.

	Note: The above SDP media description does not contain any channel-		Note: The above SDP media description does not contain any channel-
	specific information.		specific information.

	A.1. Stream Identifier Numbering		A.1. Stream Identifier Numbering

	Independently from the requested type of negotiation, the application		Independently from the requested type of negotiation, the application

	creating a data channel can either pass to the data channel stack the		creating a data channel can either pass the stream identifier to the
	stream identifier to assign to the data channel or else let the data		data channel stack to assign to the data channel or else let the data
	channel stack pick one identifier from the unused ones.		channel stack pick one identifier from the unused ones.

	To avoid glare situations, each endpoint can moreover own an		To avoid glare situations, each endpoint can moreover own an
	exclusive set of stream identifiers, in which case an endpoint can		exclusive set of stream identifiers, in which case an endpoint can
	only create a data channel with a stream identifier it owns.		only create a data channel with a stream identifier it owns.

	Which set of stream identifiers is owned by which endpoint is		Which set of stream identifiers is owned by which endpoint is
	determined by convention or other means.		determined by convention or other means.


	For data channels negotiated with the DCEP, one endpoint owns by		Note:For data channels negotiated with the DCEP, one endpoint owns
	convention the even stream identifiers, whereas the other owns the		by convention the even stream identifiers, whereas the other owns
	odd stream identifiers, as defined in		the odd stream identifiers, as defined in
	[I-D.ietf-rtcweb-data-protocol].		[I-D.ietf-rtcweb-data-protocol].


	For data channels negotiated via some protocol different from		Note:For data channels negotiated via some protocol different from
	DCEP, no convention is defined by default.		DCEP, no convention is defined by default.

	A.2. Generic Data Channel Negotiation Not Using DCEP		A.2. Generic Data Channel Negotiation Not Using DCEP

	A.2.1. Overview		A.2.1. Overview

	DCEP negotiation only provides for negotiation of data channel		DCEP negotiation only provides for negotiation of data channel
	transport parameters and does not provide for negotiation of		transport parameters and does not provide for negotiation of
	subprotocol specific parameters. DCEP-less data channel negotiation		subprotocol specific parameters. DCEP-less data channel negotiation
	can be defined to allow negotiation of parameters beyond those		can be defined to allow negotiation of parameters beyond those

End of changes. 61 change blocks.
	103 lines changed or deleted		118 lines changed or added
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