Hi, To my understanding the same SDP shall be sent in all subsequent provisional responses - no matter if they are sent reliably or not. You can only have at most one offer/answer exchange per SIP transaction, so once you've sent an offer (or answer, if the INVITE did contain an offer) in 18x you can't send any more within that transaction.
When it comes to forking, each dialog is handled completely separate from each other, ie the offer/answer "state" on one dialog is not affected by other dialog. How the UAC then chooses which dialogs to accept/reject, and how to handle possible media received from multiple UASs, is an implementation issue. Regards, Christer Holmberg Ericsson Finland > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Paul > Kyzivat > Sent: 15. helmikuuta 2005 18:42 > To: Bala Neelakantan > Cc: [email protected] > Subject: Re: [Sip-implementors] SDP in 183 non reliable response > > > > > Bala Neelakantan wrote: > > Paul, > > > > I agree that the same SDP should be sent in the subsequent > non-reliable > > response and also on the first Reliable response. > > I guess you are shifting from the subject of the original > question, and > discussing a "normal" invite that includes an offer. > > > What if the call is forked? In that case, there could be multiple > > provisional responses, each could be potentially different? > How does the > > UAC handle those? > > This has been well documented and discussed, though it can > get complex. > > The response to each fork creates a separate dialog. It is up > to the UAC > to keep the different dialogs straight until one is answered and the > others are cancelled. > > Paul > > > Thanks, > > Neel > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf > Of Paul Kyzivat > > Sent: Tuesday, February 15, 2005 9:48 AM > > To: Steven Egan > > Cc: [email protected] > > Subject: Re: [Sip-implementors] SDP in 183 non reliable response > > > > Well, I went back and read to refresh my memory. I agree > that there is > > nothing that suggests SDP might be in an unreliable > provisional when > > there had been no offer in the initial request. > > > > If it *was* there, you wouldn't be able to consider it a > true offer, > > since that must be in a reliable request or response. It > would have to > > be a hint of the offer to come. I don't find any language that > > explicitly *prohibits* this. But in the absence of anything > suggesting > > it might be valid you would be best to not count on it. > > > > Paul > > > > Steven Egan wrote: > > > >>Hi Paul, > >>So you are saying that when an INVITE is sent with no > offer, a 183 with > >>SDP can be sent in response? > >>Can you point me to where exactly this is documented please, as my > >>problem is I cannot find anything in RFC 3261 or any other > documentation > >> to confirm expected behaviour for the 183? > >>Cheers, > >>Steven > >> > >>Paul Kyzivat wrote: > >> > >> > >>> > >>>Steven Egan wrote: > >>> > >>> > >>>>Hi, > >>>>Is it valid to include the SDP in a non reliable 183 sent > in response > >>>>to an Invite with no initial offer? > >>>> > >>>>It is ok to include the SDP in the 183 when the Invite > contains the > >>>>initial offer, but RFC 3261 is not clear as to whether > the SDP can be > >>>>included when no offer is included in the initial invite. > >>> > >>> > >>> > >>>I believe the answer is YES. The *same* SDP should be sent in the > >>>first reliable response. > >>> > >>> Paul > >> > >> > > _______________________________________________ > > 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
