Thanks,

So, the UAS can not take for granted that the previous SDP is to be used
for both ways if it just ignores codec3 without terminating the session.
Right? 


Alex Zhang 
ESN: 6-554-8782 


-----Original Message-----
From: Vikram Chhibber [mailto:[EMAIL PROTECTED] 
Sent: Monday, March 17, 2008 4:40 PM
To: Alex Zhang (GDNTRND)
Cc: [EMAIL PROTECTED]; sip-implementors@lists.cs.columbia.edu
Subject: Re: [Sip-implementors] SDP Error Handling -- Unsupported codec
in SDP Answer

If the UAS continues the call, the behavior is implementation specific.
This could lead to one way media or no media at all. It may happen that
UAC sending codec-3 which UAS is not able to understand and UAS sending
previous negotiated codec that UAC may be able to process.  RFC 3264
specifies how answer should be created and does not explicitly mentions
about what to do in this scenario. Terminating the session is the most
logical thing to do in my opinion.
http://www.veraznetworks.com/
/Vikram
On Mon, Mar 17, 2008 at 1:56 PM,  <[EMAIL PROTECTED]> wrote:
> What will happen if the UAS decide to continue the call?
>  Actually, the UAC may have some errors, such as select a wrong codec

> outside the codec list of the SDP Offer. Will the continuing call 
> cause  a mismatch of the stream?
>
>  Please also give reference about this beahvior? Thanks,
>
>
>  Alex Zhang
>  ESN: 6-554-8782
>
>
>
>
>  -----Original Message-----
>  From: Madhav Bhamidipati [mailto:[EMAIL PROTECTED]
>  Sent: Monday, March 17, 2008 4:20 PM
>  To: Alex Zhang (GDNTRND)
>  Cc: sip-implementors@lists.cs.columbia.edu
>  Subject: Re: [Sip-implementors] SDP Error Handling -- Unsupported 
> codec  in SDP Answer
>
>  I wonder if it sends ACK in the first place with an unrelated codec.
>  If UAC sends a kind of
>  4XX then call continuation is still possible, i.e UAS has still an  
> option to continue the call with old parameters.
>
>  If it sends ACK then UAS sends BYE with no other option.
>
>  Madhav
>
>  On 3/17/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>  > Hi,
>  >
>  > Can anybody give guideline about the UAS Behavior as below:
>  >
>  >  UAC                               UAS
>  > <========== Session Establised=========>
>  >   |                                 |
>  >   |-----Re-invite(w/o SDP offer)--->|
>  >   |                                 |
>  >   |<----200 OK(Codec1, Codec2)------|
>  >   |                                 |
>  >   |-------ACK (Codec 3)------------>|
>  >   |                                 |
>  >   |                                 |
>  >
>  > Will UAS release the call or continue the call with the previous
SDP?
>  > Thanks,
>  >
>  > Alex
>  > _______________________________________________
>  > Sip-implementors mailing list
>  > Sip-implementors@lists.cs.columbia.edu
>  > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>  >
>
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