Re: [MMUSIC] I-D Action: draft-ietf-mmusic-msrp-usage-data-channel-10.txt - Comment on msrp-cema attribute

Christer Holmberg <> Mon, 22 April 2019 10:37 UTC

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From: Christer Holmberg <>
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Thread-Topic: [MMUSIC] I-D Action: draft-ietf-mmusic-msrp-usage-data-channel-10.txt - Comment on msrp-cema attribute
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Subject: Re: [MMUSIC] I-D Action: draft-ietf-mmusic-msrp-usage-data-channel-10.txt - Comment on msrp-cema attribute
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Section says:

   "The msrp-cema attribute SHALL be assumed to be present for every MSRP
   session using data channel transport, so the inclusion of the msrp-
   cema attribute is OPTIONAL.  This ensures that the data channel
   transport for the MSRP session is established without using the path

First, in general, I don't want attributes to be "assumed". If an extension (CEMA in this case) mandates an attribute to be included, it shall be included.

Second, I am not sure I understand the text on "ensuring that the data channel is not established using the path attribute". How would you establish a data channel using the path attribute? 



On 21/04/2019, 19.06, "mmusic on behalf of" < on behalf of> wrote:

    A New Internet-Draft is available from the on-line Internet-Drafts directories.
    This draft is a work item of the Multiparty Multimedia Session Control WG of the IETF.
            Title           : MSRP over Data Channels
            Authors         : Keith Drage
                              Maridi R. Makaraju (Raju)
                              Juergen Stoetzer-Bradler
                              Richard Ejzak
                              Jerome Marcon
                              Jose M. Recio
    	Filename        : draft-ietf-mmusic-msrp-usage-data-channel-10.txt
    	Pages           : 18
    	Date            : 2019-04-21
       This document specifies how the Message Session Relay Protocol (MSRP)
       can be instantiated as a data channel sub-protocol, using the SDP
       offer/answer exchange-based generic data channel negotiation
       framework.  Two network configurations are documented: a WebRTC end-
       to-end configuration (connecting two MSRP over data channel
       endpoints), and a gateway configuration (connecting an MSRP over data
       channel endpoint with an MSRP over TCP or TLS endpoint).
    The IETF datatracker status page for this draft is:
    There are also htmlized versions available at:
    A diff from the previous version is available at:
    Please note that it may take a couple of minutes from the time of submission
    until the htmlized version and diff are available at
    Internet-Drafts are also available by anonymous FTP at:
    mmusic mailing list