[MMUSIC] Associating packets with m-lines in a bundle

Paul Kyzivat <pkyzivat@alum.mit.edu> Thu, 23 May 2013 18:50 UTC

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Date: Thu, 23 May 2013 14:26:28 -0400
From: Paul Kyzivat <pkyzivat@alum.mit.edu>
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Subject: [MMUSIC] Associating packets with m-lines in a bundle
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After all the discussion in the meeting today, I thought it would be 
good to unwind all the indenting and start a new thread on one issue 
that is part of the "demux" problem:

IMO the following should obviously be a truism. I want to know if all agree.

If an O/A exchange negotiates a bundle with multiple m-lines,
then attributes in those m-lines and the associated media sections must 
provide sufficient information to associate each incoming packet on the 
5-tuple to exactly *one* of those m-lines.

(If it doesn't, then there was no point in including those m-lines in 
the bundle.)

For instance a=ssrc, if unique to one m-line, can bind packets with that 
SSRC to the m-line.

If a property such as SSRC is used this way, then there is the 
possibility of receiving packets that don't match any of the m-lines. I 
think we ought to address that, by defining some syntax to specify what 
to do with packets that don't match any m-line. This might be to specify 
one m-line as the default, or that packets that don't match be discarded.

This is not the complete demux problem. Added data and logic may be 
needed to decide what application processing each of those packets may 
require. Once a packet has been associated with an m-line, then some of 
the attributes associated with that m-line may provide may provide 
further information about how to decide how to process the packet. There 
can also be information that comes via other means to qualify packet