[XCON] Heads up: draft-lennox-mmusic-sdp-source-selection-00
lennox@cs.columbia.edu Wed, 05 August 2009 17:02 UTC
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Date: Wed, 05 Aug 2009 13:01:30 -0400
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From: lennox@cs.columbia.edu
Subject: [XCON] Heads up: draft-lennox-mmusic-sdp-source-selection-00
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Hello, all -- As I presented in Stockholm, I've published the Internet-Draft draft-lennox-mmusic-sdp-source-selection-00, which may be of interest to the XCON community. (Note: Vidyo has potential IPR on this draft; see <https://datatracker.ietf.org/ipr/1170/>.) The draft is based on a conference architecture where a conference server sends multiple (unmixed) streams to the conference participants, using RTP SSRC multiplexing. The draft defines an SDP-based mechanism to allow participants to explicitly request specific of these media streams, along with parameters for how they should be received (resolution, frame rate, priority). The XCON relevance is that, while it's possible to list all available sources in SDP, it's not very efficient, since SDP doesn't have partial notifications. Thus, the draft recommends that if a conference event package is running in parallel (whether it's the XCON or SIPPING packages), the event package, rather than SDP, should be used to notify particpants of the available sources. So my questions to the group are twofold. First, is this a reasonable use of the conference event packages' <src-id> element? And more fundamentally, are there reasons to try to solve this problem CCMP rather than in SDP? -- Jonathan Lennox lennox@cs.columbia.edu / jonathan@vidyo.com