Subject: [AVT] Re: MWPP slides for Yokohama available for download

From: John Lazzaro <[email-masked]>
Date: Mon, 29 Jul 2002 10:29:16 -0700

>> John Lazzaro writes
>> It wasn't clear to me if this scenareo would be legal under RFC 3264,
>> but perhaps I was misreading it in some way ...

> Colin Perkins writes:
> I don't see why it wouldn't be legal.

These paragraphs from Section 6.2:

6.2 Multicast Streams

   Unlike unicast, where there is a two-sided view of the stream, there
   is only a single view of the stream for multicast.  As such,
   generating an answer to a multicast offer generally involves
   modifying a limited set of aspects of the stream.

   If a multicast stream is accepted, the address and port information
   in the answer MUST match that of the offer.  Similarly, the
   directionality information in the answer (sendonly, recvonly, or
   sendrecv) MUST equal that of the offer.  This is because all
   participants in a multicast session need to have equivalent views of
   the parameters of the session, an underlying assumption of the
   multicast bias of RFC 2327.

---

Do customized SDP rendering parameters for different INVITEs to the
same multicast session fall into the "limited set of aspects of the stream"
that can be different for each stream, or does it violate the need for
all participants to have "equivalent views of the parameters of the session."

I'm assuming that the intent is the former ... 

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John Lazzaro -- Research Specialist -- CS Division -- EECS -- UC Berkeley
lazzaro [at] cs [dot] berkeley [dot] edu     www.cs.berkeley.edu/~lazzaro
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Audio/Video Transport Working Group
[email-masked]
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From: Colin Perkins <[email-masked]>
Date: Mon, 29 Jul 2002 13:47:07 -0400

>I'm assuming that the intent is the former ... 

I assumed the parameters of the session meant properties such as the address, 
ports, codec, etc (i.e. all receivers listen to the same session). I think
the behaviour you require is okay.

Colin