RE: [MMUSIC] SDPCapNeg Issue #5: Media before answer

Was the use of a payload type for this, as mentioned in
draft-kaplan-mmusic-best-effort-srtp-01, considered and discarded?  I'm fine
if it was, I'm just asking.  It seemed useful although it only increases the
chances of not playing garbage (because you don't know until you get the
answer if the answerer understood that technique).

-d

> -----Original Message-----
> From: Flemming Andreasen [mailto:fandreas@cisco.com] 
> Sent: Monday, June 25, 2007 10:15 AM
> To: mmusic
> Subject: [MMUSIC] SDPCapNeg Issue #5: Media before answer
> 
> The answerer may select a potential configuration containing 
> parameters that require the offerer to receive the answer 
> before he can process media correctly. The issue is explained 
> in Section 3.8 in the SDP Capability Negotiation framework, 
> where one possible solutions is outlined (preconditions), but 
> not actually specified. The question was raised whether we 
> want to say more about this issue and if we want to define 
> additional solutions to it. For example, Jonathan Rosenberg 
> suggested that use of ICE can help the answerer determine 
> when the answer has been received by the offerer and hence it 
> is safe to send media to the offerer. 
> 
> The design team discussed this issue in Prague and agreed to 
> elaborate slightly on the current text. It will be noted that 
> the offerer can discard media until he receives the answer, 
> if he wants to make sure he doesn't play garbage. If the 
> offerer wants to avoid clipping on the other hand, he can 
> play media as soon as it is received, but at the risk of 
> playing garbage. To avoid both, a three-way handshake is 
> needed (e.g. precondtion), however that is outside the basic 
> SDP Capability Negotiation. We will add a note to mention the 
> use of ICE (STUN) as a possible solution to this three-way 
> handshake as well. 
> 
> If you disagree with this, please let me know. 
> 
> Thanks
> 
> -- Flemming 
> 
> 
> 
> 
> 
> 

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