Section 14.2 of bis-09 covers most of the situation in the original post, repeated below.
A UAS providing an offer in a 2xx (because the INVITE did not contain an offer) SHOULD construct the offer as if the UAS were making a brand new call, subject to the constraints of sending an offer that updates an existing session, as described in [13] in the case of SDP. Specifically, this means that it SHOULD include as many media formats and media types that the UA is willing to support. The UAS MUST ensure that the session description overlaps with its previous session description in media formats, transports, or other parameters that require support from the peer. This is to avoid the need for the peer to reject the session description. If, however, it is unacceptable to the UAC, the UAC SHOULD generate an answer with a valid session description, and then send a BYE to terminate the session. Given this, and the behavior described in the offer-answer I-D, user 2 should be happy with user 1's answer. If not, and user 2 is compliant with the specifications, then it seems user 1's answer would be a protocol error. In this case, and like that specified for the UAC above, I would expect the UAS to send a BYE. If you apply the procedures defined for reINVITEs (stated below) the UAS can revert back to the previous session. However, given that user 1 provided an answer and user 2 "doesn't like it", one of them will probably BYE the session anyway when communications stop. Regards, Bert > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Ranjit > Avasarala > Sent: Monday, May 27, 2002 12:19 AM > To: Attila Sipos; 'Feldman, Michael'; [EMAIL PROTECTED] > Subject: Re: [Sip-implementors] reinvite question > > > Hi > > But as per the bis-09 the call should not be terminated if > re-invite > fails. The call should be restored with the oriiginal session > paramters > > so I feel u should not send BYE > > Ranjit > ----- Original Message ----- > From: "Attila Sipos" <[EMAIL PROTECTED]> > To: "'Feldman, Michael'" <[EMAIL PROTECTED]>; "'Ranjit > Avasarala'" > <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> > Sent: Friday, May 24, 2002 11:10 PM > Subject: RE: [Sip-implementors] reinvite question > > > > Hi Mike, > > > > I have a quote here from "draft-ietf-mmusic-sdp-offer-answer-02.txt" > > which may be of help: > > > > The offer/answer exchange > is atomic; if > > the answer is rejected, the session reverts to the state > prior to the > > offer (which may be absence of a session). > > > > To me it seems that if the SDP "answer" in the ACK is NOT a codec > > contained in the "offer" then can we not consider this to be a > > rejection? > > > > If so, then you should revert back to the state you were in > before the > > INVITE was sent. If that means that a call wasn't up, then the call > > should be terminated (I would send a BYE to make sure it is). > > > > Regards, > > > > Attila > > > > <http://www.vegastream.com> > > VegaStream : A World of difference for your Integrated > Communications > > > > > > > -----Original Message----- > > > From: Feldman, Michael [mailto:[EMAIL PROTECTED]] > > > Sent: 23 May 2002 15:14 > > > To: 'Ranjit Avasarala'; [EMAIL PROTECTED] > > > Subject: RE: [Sip-implementors] reinvite question > > > > > > > > > If you want to change the codec for instance... > > > (mind you I do not know why the user2 would want to reject > > > the re-invite > > > because user1 should be using a codec offered in the 200ok...) > > > > > > mike > > > > > > -----Original Message----- > > > From: Ranjit Avasarala [mailto:[EMAIL PROTECTED]] > > > Sent: Wednesday, May 22, 2002 10:55 PM > > > To: Feldman, Michael; [EMAIL PROTECTED] > > > Subject: Re: [Sip-implementors] reinvite question > > > > > > > > > Hi > > > re-invite is sent when u want to change the session > > > parameters, but I > > > don't see any such thing here. so why do u want to use re-invite? > > > > > > Ranjit > > > ----- Original Message ----- > > > From: "Feldman, Michael" <[EMAIL PROTECTED]> > > > To: <[EMAIL PROTECTED]> > > > Sent: Wednesday, May 22, 2002 11:07 PM > > > Subject: [Sip-implementors] reinvite question > > > > > > > > > > when you have a re-invite, how does the far end reject the > > > changes in > > > > the > > > > following case... > > > > (mind you I am not sure when this would happen) > > > > > > > > > > > > Call in progress... > > > > user1 > > > > user2 > > > > Invite (no SDP information) --> > > > > <-- 200 OK (with SDP information) > > > > ACK (with SDP information) --> > > > > > > > > user 2 does not like the information given in the ACK by user1, > > > > a bye does not make sense since we do not want to terminate > > > the call. > > > > > > > > > > > > > > > > thanks, > > > > mike > > > > > > > > _______________________________________________ > > > > Sip-implementors mailing list > > > > [EMAIL PROTECTED] > > > > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > > > _______________________________________________ > > > Sip-implementors mailing list > > > [EMAIL PROTECTED] > > > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > > > > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
