Hi Alex, Generallym if the audio codec is non-understandable to the UAS, it can accept the dialog which is trying to get established. But if the audio codec mismatch happens, based on its implementation dependency, it tries to terminate the session as it is unable to understand. In this case, in the BYE request message, the UAS sends a Reason header, which will specify the cause of this immediate session termination. This reason cause values are generated by the ITU's specs. These specs you can search in the Inet and go thru them, if the UAC is getting BYE with some reason header.
Regards, Santosh Karankoti -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, March 17, 2008 2:24 PM To: [EMAIL PROTECTED] Cc: sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] SDP Error Handling -- Unsupported codec inSDP Answer One key factor on this problem is that: Will the UAC MUST change the session attributes as its generated Answer right the asnwer is sent out? I really don't see any subsequent message from UAS to notify the Codec 3 is not supported by UAS. 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 > > > > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
