That's one reason why I have seen most implementations use re-invites instead of updates for mid call changes. Why leave a possibility of 2 transactions when one can live with 1. But then its implementation specific :-)
Thnx -----Original Message----- From: Brett Tate <[EMAIL PROTECTED]> To: Manpreet Singh CC: [EMAIL PROTECTED] <[EMAIL PROTECTED]>; sip-implementors@lists.cs.columbia.edu <sip-implementors@lists.cs.columbia.edu> Sent: Mon Apr 14 09:04:10 2008 Subject: RE: [Sip-implementors] Offer/Answer question I agree with Paul; however I'll highlight the rfc3311 section 5.2 text concerning UPDATE with SDP potentially triggering a 504. Thus UAC receiving 504 for UPDATE with SDP should be aware that a re-INVITE might be needed to perform the SDP modification. "If the UAS cannot change the session parameters without prompting the user, it SHOULD reject the request with a 504 response." > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Paul Kyzivat > Sent: Monday, April 14, 2008 12:34 AM > To: Manpreet Singh > Cc: Bob Penfield; [EMAIL PROTECTED]; > sip-implementors@lists.cs.columbia.edu > Subject: Re: [Sip-implementors] Offer/Answer question > > > > Manpreet Singh wrote: > > Wasn't denying the use of update on confirmed dialog, just > saying the > > recommended use of UPDATE is for early dialog and not for confirmed > > based on the spec. > > > > ""Although UPDATE can be used on confirmed dialogs, it is > RECOMMENDED > > that a re-INVITE be used instead. This is because an UPDATE > needs to > > be answered immediately, ruling out the possibility of user > approval. > > Such approval will frequently be needed, and is possible with a > > re-INVITE."" > > IMO the "denial" is a bit overstated. It is only pointing out > that its inappropriate if the offer it carries will require > an extended time for approval before being answered. If that > isn't to be the case then there isn't any issue with using UPDATE. > > Note that the issue with immediate response also applies to > an UPDATE used during an early dialog. > > Paul _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors