--- 1/draft-ietf-mmusic-data-channel-sdpneg-05.txt 2015-10-19 10:16:07.856259187 -0700 +++ 2/draft-ietf-mmusic-data-channel-sdpneg-06.txt 2015-10-19 10:16:07.928260943 -0700 @@ -1,22 +1,22 @@ MMUSIC K. Drage, Ed. Internet-Draft M. Makaraju Intended status: Standards Track J. Stoetzer-Bradler -Expires: April 7, 2016 Alcatel-Lucent +Expires: April 21, 2016 Alcatel-Lucent R. Ejzak J. Marcon Unaffiliated - October 5, 2015 + October 19, 2015 SDP-based Data Channel Negotiation - draft-ietf-mmusic-data-channel-sdpneg-05 + draft-ietf-mmusic-data-channel-sdpneg-06 Abstract The Real-Time Communication in WEB-browsers (RTCWeb) working group is charged to provide protocols to support direct interactive rich communications using audio, video, and data between two peers' web- browsers. For the support of data communication, the RTCWeb working group has in particular defined the concept of bi-directional data channels over SCTP, where each data channel might be used to transport other protocols, called sub-protocols. Data channel setup @@ -36,21 +36,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference 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 (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -62,72 +62,74 @@ Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Applicability Statement . . . . . . . . . . . . . . . . . . . 5 5. SDP Offer/Answer Negotiation . . . . . . . . . . . . . . . . 5 5.1. SDP Syntax . . . . . . . . . . . . . . . . . . . . . . . 5 5.1.1. SDP Attribute for Data Channel Parameter Negotiation 5 - 5.1.1.1. dcmap Attribute . . . . . . . . . . . . . . . . . 5 - 5.1.1.2. dcmap Multiplexing Category . . . . . . . . . . . 7 - 5.1.1.3. dcmap-stream-id Parameter . . . . . . . . . . . . 7 - 5.1.1.4. label Parameter . . . . . . . . . . . . . . . . . 7 - 5.1.1.5. subprotocol Parameter . . . . . . . . . . . . . . 8 - 5.1.1.6. max-retr Parameter . . . . . . . . . . . . . . . 8 - 5.1.1.7. max-time Parameter . . . . . . . . . . . . . . . 8 - 5.1.1.8. ordered Parameter . . . . . . . . . . . . . . . . 8 - 5.1.2. Sub-Protocol Specific Attributes . . . . . . . . . . 9 - 5.1.2.1. dcsa Attribute . . . . . . . . . . . . . . . . . 9 - 5.1.2.2. dcsa Multiplexing Category . . . . . . . . . . . 10 - 5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . 10 - 5.2.1. Managing Stream Identifiers . . . . . . . . . . . . . 10 - 5.2.2. Negotiating Data Channel Parameters . . . . . . . . . 11 - 5.2.3. Opening a Data Channel . . . . . . . . . . . . . . . 12 - 5.2.4. Closing a Data Channel . . . . . . . . . . . . . . . 14 - 5.2.5. Various SDP Offer/Answer Scenarios and Considerations 15 - 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 16 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 - 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 - 8.1. Subprotocol Identifiers . . . . . . . . . . . . . . . . . 18 - 8.2. New SDP Attributes . . . . . . . . . . . . . . . . . . . 19 - 8.2.1. dcmap . . . . . . . . . . . . . . . . . . . . . . . . 19 - 8.2.2. dcsa . . . . . . . . . . . . . . . . . . . . . . . . 19 + 5.1.1.1. dcmap Attribute . . . . . . . . . . . . . . . . . 6 + 5.1.1.2. dcmap Multiplexing Category . . . . . . . . . . . 8 + 5.1.1.3. dcmap-stream-id Parameter . . . . . . . . . . . . 8 + 5.1.1.4. label Parameter . . . . . . . . . . . . . . . . . 8 + 5.1.1.5. subprotocol Parameter . . . . . . . . . . . . . . 9 + 5.1.1.6. max-retr Parameter . . . . . . . . . . . . . . . 9 + 5.1.1.7. max-time Parameter . . . . . . . . . . . . . . . 9 + 5.1.1.8. ordered Parameter . . . . . . . . . . . . . . . . 9 + 5.1.2. Other Media Level Attributes . . . . . . . . . . . . 10 + 5.1.2.1. dcsa Attribute . . . . . . . . . . . . . . . . . 10 + 5.1.2.2. dcsa Multiplexing Category . . . . . . . . . . . 11 + 5.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . 11 + 5.2.1. Managing Stream Identifiers . . . . . . . . . . . . . 11 + 5.2.2. Negotiating Data Channel Parameters . . . . . . . . . 12 + 5.2.3. Opening a Data Channel . . . . . . . . . . . . . . . 13 + 5.2.4. Closing a Data Channel . . . . . . . . . . . . . . . 15 + 5.2.5. Various SDP Offer/Answer Scenarios and Considerations 16 + 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 17 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 19 + 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 + 8.1. Subprotocol Identifiers . . . . . . . . . . . . . . . . . 19 + 8.2. New SDP Attributes . . . . . . . . . . . . . . . . . . . 20 + 8.2.1. dcmap . . . . . . . . . . . . . . . . . . . . . . . . 20 + 8.2.2. dcsa . . . . . . . . . . . . . . . . . . . . . . . . 20 - 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 - 10. CHANGE LOG . . . . . . . . . . . . . . . . . . . . . . . . . 20 + 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21 + 10. CHANGE LOG . . . . . . . . . . . . . . . . . . . . . . . . . 21 10.1. Changes against 'draft-ietf-mmusic-data-channel- - sdpneg-04' . . . . . . . . . . . . . . . . . . . . . . . 20 + sdpneg-05' . . . . . . . . . . . . . . . . . . . . . . . 21 10.2. Changes against 'draft-ietf-mmusic-data-channel- - sdpneg-03' . . . . . . . . . . . . . . . . . . . . . . . 21 + sdpneg-04' . . . . . . . . . . . . . . . . . . . . . . . 22 10.3. Changes against 'draft-ietf-mmusic-data-channel- - sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 22 + sdpneg-03' . . . . . . . . . . . . . . . . . . . . . . . 23 10.4. Changes against 'draft-ietf-mmusic-data-channel- - sdpneg-01' . . . . . . . . . . . . . . . . . . . . . . . 23 + sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 24 10.5. Changes against 'draft-ietf-mmusic-data-channel- - sdpneg-00' . . . . . . . . . . . . . . . . . . . . . . . 25 - 10.6. Changes against 'draft-ejzak-mmusic-data-channel- - sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 28 - 10.7. Changes against '-01' . . . . . . . . . . . . . . . . . 29 - 10.8. Changes against '-00' . . . . . . . . . . . . . . . . . 29 - 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 - 11.1. Normative References . . . . . . . . . . . . . . . . . . 30 - 11.2. Informative References . . . . . . . . . . . . . . . . . 30 + sdpneg-01' . . . . . . . . . . . . . . . . . . . . . . . 25 + 10.6. Changes against 'draft-ietf-mmusic-data-channel- + sdpneg-00' . . . . . . . . . . . . . . . . . . . . . . . 27 + 10.7. Changes against 'draft-ejzak-mmusic-data-channel- + sdpneg-02' . . . . . . . . . . . . . . . . . . . . . . . 30 + 10.8. Changes against '-01' . . . . . . . . . . . . . . . . . 31 + 10.9. Changes against '-00' . . . . . . . . . . . . . . . . . 31 + 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 31 + 11.1. Normative References . . . . . . . . . . . . . . . . . . 32 + 11.2. Informative References . . . . . . . . . . . . . . . . . 32 Appendix A. Generic Data Channel Negotiation Aspects When Not - Using DCEP . . . . . . . . . . . . . . . . . . . . . 32 - A.1. Stream Identifier Numbering . . . . . . . . . . . . . . . 32 - A.2. Generic Data Channel Negotiation Not Using DCEP . . . . . 33 - A.2.1. Overview . . . . . . . . . . . . . . . . . . . . . . 33 - A.2.2. Opening a Data Channel . . . . . . . . . . . . . . . 33 - A.2.3. Closing a Data Channel . . . . . . . . . . . . . . . 34 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 + Using DCEP . . . . . . . . . . . . . . . . . . . . . 34 + A.1. Stream Identifier Numbering . . . . . . . . . . . . . . . 34 + A.2. Generic Data Channel Negotiation Not Using DCEP . . . . . 35 + A.2.1. Overview . . . . . . . . . . . . . . . . . . . . . . 35 + A.2.2. Opening a Data Channel . . . . . . . . . . . . . . . 35 + A.2.3. Closing a Data Channel . . . . . . . . . . . . . . . 36 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 1. Introduction The RTCWeb working group has defined the concept of bi-directional 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 in-band or out-of-band protocols for creating them. Each data channel consists of paired SCTP streams sharing the same SCTP Stream Identifier. Data channels are created by endpoint applications through the WebRTC API, or other users of data channel like CLUE, and @@ -138,20 +140,27 @@ 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 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 channel stack includes no channel-specific information. This document defines SDP offer/answer negotiation procedures to establish data channels for transport of well-defined sub-protocols, 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 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 3. Terminology This document uses the following terms: @@ -290,29 +299,30 @@ one 'maxretr-opt' parameter or one 'maxtime-opt' parameter MAY be present. Both MUST NOT be present. 5.1.1.2. dcmap Multiplexing Category Multiplexing characteristics of SDP attributes are described in [I-D.ietf-mmusic-sdp-mux-attributes]. Various SDP attribute multiplexing categories are introduced there. 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 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/ - SCTP proto values. If future extensions of + "a=dcmap:" attribute multiplexing rules are specified for the + 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 - 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 well, for instance in an extension of this SDP based data channel negotiation specification. 5.1.1.3. dcmap-stream-id Parameter The 'dcmap-stream-id' parameter indicates the SCTP stream identifier within the SCTP association used to form the data channel. 5.1.1.4. label Parameter @@ -328,21 +338,21 @@ Note: The empty string MAY also be explicitly used as 'label' value, such that 'label=""' is equivalent to the 'label' parameter not being present at all. [I-D.ietf-rtcweb-data-protocol] allows the DATA_CHANNEL_OPEN message's 'Label' value to be an empty string. 5.1.1.5. subprotocol Parameter The 'subprotocol' parameter indicates which protocol the client expects to exchange via the channel. This parameter maps to the '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 'subprotocol' parameter is not present, then its value defaults to the empty string. Note: The empty string MAY also be explicitly used as 'subprotocol' value, such that 'subprotocol=""' is equivalent to the 'subprotocol' parameter not being present at all. [I-D.ietf-rtcweb-data-protocol] allows the DATA_CHANNEL_OPEN message's 'Subprotocol' value to be an empty string. @@ -372,41 +382,45 @@ The 'ordered' parameter with value "true" indicates that the receiver MUST dispatch DATA chunks in the data channel to the upper layer while preserving the order. The ordered parameter is optional and takes two values: "true" for ordered and "false" for unordered delivery with "true" as the default value. Any other value is ignored and default "ordered=true" is assumed. In the absence of this parameter "ordered=true" is assumed. This parameter maps to the ordered or unordered data channel types as defined in [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 - other SDP attributes specific to the sub-protocol in use. Each of - these attributes is represented by one new attribute line, and it - includes the contents of a media-level SDP attribute already defined - for use with this (sub)protocol in another IETF specification. Sub- - protocol-specific attributes might also be defined for exclusive use - with data channel transport, but should use the same syntax described - here for other sub-protocol-specific attributes. + other media level SDP attributes, which are either specifically + defined for or applied to the sub-protocol in use. Each of these + attributes is represented by one new attribute line, and it includes + the contents of a media-level SDP attribute already defined for use + with this (sub-)protocol in another IETF specification. Sub-protocol + specific attributes MAY also be defined for exclusive use with data + channel transport, but SHOULD use the same syntax described here for + other sub-protocol related attributes. 5.1.2.1. dcsa Attribute - Each sub-protocol specific SDP attribute that would normally be used - to negotiate the subprotocol using SDP is replaced with an attribute + Each sub-protocol related SDP attribute that would normally be used + to negotiate the sub-protocol using SDP is replaced with an attribute of the form "a=dcsa:stream-id original-attribute", where dcsa stands for "data channel sub-protocol attribute", stream-id is the SCTP stream identifier assigned to this sub-protocol instance, and original-attribute represents the contents of the sub-protocol 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: Name: dcsa Value: dcsa-value Usage Level: media Charset Dependent: no @@ -422,49 +436,41 @@ Note that the above reference to RFC 4566 defines where the attribute definition can be found; it does not provide any limitation on support of attributes defined in other documents in accordance with this attribute definition. Note however that not all SDP attributes are suitable as "a=dcsa:" parameter. [IANA-SDP-Parameters] contains the lists of IANA registered session and media level or media level only SDP attributes. 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. + accept-types:text/plain", which specifies that this instance of the + MSRP sub-protocol being transported on the SCTP association using the + data channel with stream id 2 accepts plain text files. As opposed to the data channel "a=dcmap:" attribute parameters, these parameters are subject to offer/answer negotiation following the 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 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 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/ - SCTP proto values. If future extensions of + "a=dcsa:" attribute multiplexing rules are specified for the + 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 - 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 well, for instance in an extension of this SDP based data channel negotiation specification. 5.2. Procedures 5.2.1. Managing Stream Identifiers 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 @@ -503,21 +509,21 @@ channel is achieved by including only one of 'max-retr' or 'max- 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 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 answer contains both of these parameters then the offerer MAY treat it as an error and MAY assume the associated SDP offer/answer failed and MAY take appropriate recovery actions. These recovery options 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 include a label parameter. They MAY appear in any order, which could be different from the SDP offer, in the SDP answer. 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 information. Data channel types defined in [I-D.ietf-rtcweb-data-protocol] are mapped to SDP in the following manner, where "ordered=true" is the @@ -821,21 +827,21 @@ 7. Security Considerations No security considerations are envisaged beyond those already documented in [RFC4566]. 8. IANA Considerations 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". The following text should be added following the title of the table. "This table also includes subprotocol identifiers specified for usage within a WebRTC data channel." The following reference should be added to under the heading reference: "RFC XXXX". @@ -854,70 +860,108 @@ This document defines a new SDP media-level attribute "a=dcmap:" as follows: +---------------------+-----------------------------------------+ | Attribute name: | dcmap | | Type of attribute: | media | | Mux category: | SPECIAL | | Charset Dependent: | No | | Purpose: | Define data channel specific parameters | | Appropriate values: | As defined in Section 5.1.1 | - | Contact name: | Maridi R. Makaraju (Raju) | - | Contact e-mail: | Raju.Makaraju@alcatel-lucent.com | + | Contact name: | MMUSIC Chairs | + | Contact e-mail: | mmusic-chairs@ietf.org | | Reference: | RFCXXXX | +---------------------+-----------------------------------------+ 8.2.2. dcsa NOTE to RFC Editor: Please replace "XXXX" with the number of this RFC. This document defines a new SDP media-level attribute "a=dcsa:" as follows: +---------------------+---------------------------------------------+ | Attribute name: | dcsa | | Type of attribute: | media | | Mux category: | SPECIAL | | Charset Dependent: | No | | Purpose: | Define data channel sub-protocol specific | | | attributes | | Appropriate values: | As defined in Section 5.1.2 | - | Contact name: | Maridi R. Makaraju (Raju) | - | Contact e-mail: | Raju.Makaraju@alcatel-lucent.com | + | Contact name: | MMUSIC Chairs | + | Contact e-mail: | mmusic-chairs@ietf.org | | Reference: | RFCXXXX | +---------------------+---------------------------------------------+ 9. Acknowledgments The authors wish to acknowledge the borrowing of ideas from other internet drafts by Salvatore Loreto, Gonzalo Camarillo, Peter Dunkley - and Gavin Llewellyn, and to thank Roni Even, Christian Groves, - Christer Holmberg, Paul Kyzivat, Jonathan Lennox, and Uwe + and Gavin Llewellyn, and to thank Roni Even, Christian Groves, Gunnar + Hellstrom, Christer Holmberg, Paul Kyzivat, Jonathan Lennox, and Uwe Rauschenbach for their invaluable comments. 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 'subprotocol' parameter indicates which protocol the client expects to exchange via the channel. 'Subprotocol' is an optional parameter. If the 'subprotocol' parameter is not present, then its value defaults to the empty string." Replacement of this paragraph with following two paragraphs: * The 'subprotocol' parameter indicates which protocol the client expects to exchange via the channel. This parameter maps to the 'Protocol' parameter defined in [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 present, then its value defaults to the empty string. * Note: The empty string MAY also be explicitly used as 'subprotocol' value, such that 'subprotocol=""' is equivalent to the 'subprotocol' parameter not being present at all. [I-D.ietf-rtcweb-data-protocol] allows the DATA_CHANNEL_OPEN message's 'Subprotocol' value to be an empty string. o Addition of [I-D.ietf-mmusic-sdp-mux-attributes] to list the of @@ -931,21 +975,21 @@ 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 related mux category section are similar to the "Mux Category" sections of the "a=sctp-port:" and "a=max-message-size:" attributes in [I-D.ietf-mmusic-sctp-sdp]. o Addition of new Section 5.1.2.2 describing the mux category of the 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 applications to use data channels and its in-band DCEP or out-of- 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 protocols for creating them". Additionally replacement of "In particular, the SDP offer generated by the application includes no channel-specific information" with "... generated by the RTCweb data channel stack includes no channel-specific information". @@ -989,21 +1033,21 @@ o In Section 5.2.1 replacement of "However, an SDP offer/answer exchange MUST NOT be initiated if the associated SCTP stream is already negotiated via DCEP" with "However, an SCTP stream MUST NOT be referenced in a dcmap or dcsa attribute of an SDP offer/ answer exchange if the associated SCTP stream has already been negotiated via DCEP". o In the examples in Section 6 addition of the previously missing 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 normative references to the list of informative references. o Addition of [IANA-SDP-Parameters] to the list of informative references and addition of following two sentences to the first paragraph after the ABNF definition: "Note however that not all SDP attributes are suitable as "a=dcsa:" parameter. [IANA-SDP-Parameters] contains the lists of IANA registered session and media level or media level only SDP attributes." @@ -1038,21 +1082,21 @@ a=dcmap". o Move of reference [WebRtcAPI] from list of normative references to list of informative references. o Removal of almost all text parts, which discussed JavaScript or other API specific aspects. Such API specific aspects were mainly discussed in sub-sections of Section 5 and Section 5 of draft- 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 Addition of new Section 8.1 "Subprotocol identifiers" as subsection of the "IANA Considerations" related Section 8. Also removal of the temporary note "To be completed. As [I-D.ietf- rtcweb-data-protocol] this document should refer to IANA's WebSocket Subprotocol Name Registry defined in [RFC6455]." o In Section 5.2.2: @@ -1140,21 +1184,21 @@ * In the last but one paragraph replacement of "must" with "The application MUST also close...". o In Section 5.1.2 addition of following note after the formal definition of the 'a=dcsa' attribute: "Note that the above reference to RFC 4566 defines were the attribute definition can be found; it does not provide any limitation on support of attributes defined in other documents in accordance with this attribute 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 channel consisting of paired SCTP outbound and inbound streams." Replacement of this definition with "Data channel: A WebRTC data channel as specified in [I-D.ietf-rtcweb-data-channel]", and consistent usage of "data channel" in the remainder of the document including the document's headline." 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. @@ -1270,21 +1314,21 @@ 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 successful SDP offer/answer." o Although dedicated to "a=dcmap" and "a=dcsa" SDP syntax aspects Section 5.1.1 contained already procedural descriptions related to data channel reliability negotiation. Creation of new Section 5.2.2 and moval of reliability negotiation related text to 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 parameter". As [I-D.ietf-rtcweb-data-protocol] this document should refer to IANA's WebSocket Subprotocol Name Registry defined in [RFC6455]. o In whole document, replacement of "unreliable" with "partially reliable", which is used in [I-D.ietf-rtcweb-data-channel] and in [I-D.ietf-rtcweb-data-protocol] in most places. @@ -1320,32 +1364,32 @@ o In the "Examples" section, in the first two SDP offer examples in the a=dcmap attribute lines 'label="BGCP"' was replaced with 'label="BFCP"'. o In all examples, the "m" line proto value "DTLS/SCTP" was replaced with "UDP/DTLS/SCTP" and the "a=fmtp" attribute lines were replaced with "a=max-message-size" attribute lines, as per draft- 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 Making subprotocol as an optional parameter in dcmap. o Specifying disallowed parameter combinations for max-time and max- retr. 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 negotiation and their usage. o Introduction of more generic terminology, e.g. "application" instead of "browser". o Clarification of how "max-retr and max-time affect the usage of unreliable and reliable WebRTC data channels. @@ -1433,22 +1476,22 @@ . [RFC6714] Holmberg, C., Blau, S., and E. Burger, "Connection Establishment for Media Anchoring (CEMA) for the Message Session Relay Protocol (MSRP)", RFC 6714, DOI 10.17487/RFC6714, August 2012, . [I-D.ietf-rtcweb-jsep] Uberti, J., Jennings, C., and E. Rescorla, "Javascript - Session Establishment Protocol", draft-ietf-rtcweb-jsep-11 - (work in progress), July 2015. + Session Establishment Protocol", draft-ietf-rtcweb-jsep-12 + (work in progress), October 2015. [IANA-SDP-Parameters] "Session Description Protocol (SDP) Parameters", Internet Assigned Numbers Authority Protocol Assignments Session Description Protocol (SDP) Parameters, . [WebRtcAPI] Bergkvist, A., Burnett, D., Jennings, C., and A.