Subject: Protocol Action: SDP: Session Description Protocol to Proposed Standard

From: The IESG <[email-masked]>
Date: Mon, 06 Apr 1998 06:56:00 -0400

The IESG has approved the Internet-Draft SDP: Session Description
Protocol <draft-ietf-mmusic-sdp-07.txt,.ps> as a Proposed Standard.  This
document is the product of the Multiparty Multimedia Session Control
Working Group.  The IESG contact persons are Allyn Romanow and Scott
Bradner.

Technical Summary

Session Description Protocol (SDP) describes a format for describing
real-time multimedia sessions. SDP is widely used on the Internet
multicast backbone (Mbone) in a session directory tool which advertises
multimedia conferences and information necessary for participation in
the conference. SDP is intended to be used by different transport
protocols, such as Session Announcement Protocol (SAP), Session
Initiation Protocol (SIP), Real-Time Streaming Protocol (RTSP),
electronic mail using MIME extensions, and the Hypertext Transport
Protocol.

Working Group Summary

SDP has evolved in mmusic and in the user community over several years.
It now widely used and there are no remaining points of contention.

Protocol Quality

This document was reviewed for the IETF by Allyn Romanow.

The following implementations exist:

        UCL/ISI Session Directory tool sdr
        Cisco routers
        CDT mAnnouncer from Lulea University
        Precept Software's IP/TV Program Guide
        ICAST's Viewer and Guide
        the RTSP Reference Implementation
        RealNetwork's RealMedia SDK
        W3C's Jigsaw
        IBM's RTSP Toolkit
        GMD Fokus's SIPD
        Columbia University's jsipd
        UCL's Java Internet Phone
        Mediatrix's Audiotric Phone Adapto

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From: Mark Handley <[email-masked]>
Date: Mon, 06 Apr 1998 12:03:51 -0400

>Working Group.  The IESG contact persons are Allyn Romanow and Scott

Just in case anyone is wondering why they didn't see the -07 draft
before today, this version was produced during the IETF last week as a
result of detailed discussion with the members of the IESG who had
raised issues with the -06 draft.  Approval had been dependant on them
signing off these final minor changes.

The changes that were required for final approval were:

 - allowing fully-qualified domain names in c= and o= fields so SDP
   could work in the presence of NATs.

 - changing the registration rules for (non-RTP) formats.  SDP format
   names will now be registered in the MIME-types namespace.  Hence
   registering a format to use in the SDP line:
     m=application 1234 udp wb
   would require a registration of the MIME content-type application/wb.

   This is an interesting change to the use of the MIME-types
   registration process, as wb (for example) has no appropriate file 
   format.  It remains to be seen how this is implemented in practice,
   but the relevant IESG members have agreed to this, and I agree with
   them that it is a good idea.

The one change I'd have liked to have made is removing the 1 Kbyte
size limit (which was intended to only apply to SAP, not to SDP in
other contexts).  However, I couldn't make any changes not explicitly
requested by the IESG without requiring another full IESG ballot,
which would have caused a whole new set of delays.

I propose that this change will be made when SDP moves to Draft
Standard, and so implementations would be advised to accept session
descriptions of arbitrary length (if they're conveyed by means other
than SAP), even though they're not strictly legal.

Cheers,
	Mark