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Re: [MMUSIC] SDPCapNeg : 2nd o/a via UPDATE?



Hi Bob:

That's a new interesting point for me, but I'm not sure I follow it:
How could you avoid second O/A exchang when precondition is needed.

Alice need to signal to you (Bob) the "a=inactive" to "a=sendrecv"
change isn't it? could this really be fixed by media capabilities
extention without second O/A?  

pls treat this only as one question instead of a counterexample.

BR
Zhengrong

 

-----Original Message-----
From: Bob Gilman [mailto:bob_gilman at comcast.net] 
Sent: den 10 april 2008 22:10
To: Flemming Andreasen
Cc: Zhengrong Yao; mmusic at ietf.org
Subject: Re: [MMUSIC] SDPCapNeg : 2nd o/a via UPDATE?

Flemming-
Thanks for reminding me of the problem of old middleboxes.
I was thinking of the 1 of N codec selection problem in section
10.2 of RFC 3264.
-Bob
-------------------------------------------------------------
Bob Gilman        bob_gilman at comcast.net      +1 303 898 9780



Flemming Andreasen wrote:
> The second O/A exchange is technically speaking never needed; it's 
> done as a courtesy to any potential middle-boxes that may not 
> understand the SDP capability negotiations.
> 
> -- Flemming
> 
> Bob Gilman wrote:
>> I think it's always possible, using media capabilities, to frame an 
>> offer such that there is no need for a second O/A exchange.
>> I'd be interested in seeing counterexamples.
>> -Bob
>> -------------------------------------------------------------
>> Bob Gilman        bob_gilman at comcast.net      +1 303 898 9780

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