[MMUSIC] SCTP question: Where does it multiplex?

Harald Alvestrand <harald@alvestrand.no> Fri, 02 November 2012 10:39 UTC

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Date: Fri, 02 Nov 2012 11:39:05 +0100
From: Harald Alvestrand <harald@alvestrand.no>
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Subject: [MMUSIC] SCTP question: Where does it multiplex?
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As currently specified, the DTLS/SCTP protocol is carefully specified in 
such a way that it can ride on the same 5-tuple as an SRTP session. I'd 
like to keep that property when we SDP-negotiate it.

The proposed syntax for DTLS/SCTP seems to be

m=<something, likely application> <port number> DTLS/SCTP <fmt data, 
mostly meaningless>

I see two ways to define this as a multiplex:

- Give the same port number as another m= line in the same SDP session
- Give a meaningless port number, and use the a=group:BUNDLE (of 
whatever flavor) to give which port number it's actually multiplexed 
together with.

The best way to do this may be obvious after the BUNDLE discussion, but 
in case there are other considerations .... are there thoughts?

                Harald