[XCON] Heads up: draft-lennox-mmusic-sdp-source-selection-00

[lennox at cs.columbia.edu]

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 at cs.columbia.edu / jonathan at vidyo.com