Hi,

>The offerer need to be able to receive any codec that he declared in the offer 
>regardless of answer.

Before or after he has received the answer?

BEFORE he has received the answer he may accept anything that was in the offer 
(eventhough in many cases he will not accept - or even receive (due to gates 
etc) - anything until he has received the answer).

AFTER he has received the answer he may accept only what both parties have 
indicated support for.


>The offerer may send a re-invite after the answer to fix the set of codecs to 
>a smaller set.

That is normally done when both the offer and the answer have contained 
multiple codecs which both support.

But, if I offer you A, B and C, and you send back C, I am not necessarily going 
to send a re-INVITE to "remove" A and B - I may assume that we will only use C 
(based on the text from 3264 we've seen cited in this thread).

Regards,

Christer

 

 


Roni Even

> -----Original Message-----
> From: Christer Holmberg [mailto:[EMAIL PROTECTED]
> Sent: Friday, November 23, 2007 12:48 PM
> To: Dean Willis
> Cc: [email protected]
> Subject: RE: [Sip] SIPit 21 : Topics that attendees argued about
>
> Hi,
>
> >> I agree with Ravi.
> >>
> >> Eventhough you in theory is supposed to be able to receive what you
> >> offer - no matter what you get in the answer - I think that in real
> >> life the only codecs that participants will be prepared to send/receive
> are
> >> the ones sent both in the offer and the answer. That is also the
> >> reason
> >> why the answer normally doesn't contain additional codecs - it mostly
> >> contains a subset of the codecs in the offer.
> >So how do you deal with asymmetric encoding?
>
> You may use different codecs in each direction (eventhough I don't think
> it happens very often), as long as all codecs have been present in both
> the offer and the answer.
>
> Regards,
>
> Christer
>
>
>
>
>
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