So it is possible for a UAS to change To tag in each provisional response it send until it finaly sends a 200 OK, where that To tag need to be kept during the dialog? And UAC must be able to update the remote tag value for each provisional response and finaly set it permanent when it receives the 200 OK?
To clearify the sip messages sent: when the Proxy sends the cancel, it also stops all responses from UA2, this so that no 487 should reach UA1 (the call will in that case end). // Andreas -----Original Message----- From: Sankaran Narayanan [mailto:[EMAIL PROTECTED] Sent: den 16 augusti 2003 22:15 To: Andreas Bystr�m Subject: Re: [Sip-implementors] To tag when forking requests the final dialog will use the To tag used by UA3 since a dialog was never established with UA2( as the proxy sent a cancel) On Fri, 15 Aug 2003, [iso-8859-1] Andreas Bystr�m wrote: > Hi all! > > A question about To tags. This is the scenario I have in mind: > > * UA1 calls [EMAIL PROTECTED] via the proxy P. > * P knows that [EMAIL PROTECTED] should be forwarded to UA2. > * UA2 responds to the Invite with a 180 Ringing and has added a To tag to > the response. > * After a period of time, logic in P notices that UA2 hasn't answered the > call yet. Then P has instructions to try at UA3 instead, so it sends Cancel > to UA2 and sends the origianl Invite to UA3. > * UA3 now answers with 180 Ringing with a new To tag since it has no idea of > the To tag that UA2 sent. > * UA3 send 200 OK and the call is set up. > > My quesiton is that isn't not allowed to change the To tag within a dialog > since it is used to identify a call? Is it possible to do my scenario? Could > it be solved in that way that before P forwards the Invite to UA3, it adds > tha To tag that UA2 sent in the first 180? I think I've read somewhere that > you are not allowed to put the To tag inside an Invite (if it is not an > re-Invite), is this correct? Should I solve the forward on no reply in some > other way? > > Appreciate to hear your thoughts in this matter. > > Regards, > Andreas > > ____________________________________ > Andreas Bystrom > Computer Engineer > > e-horizon Streaming Technologies > Stadshusplatsen 2, 4th floor > Box 172 > SE 14922 Nynashamn > > mail : [EMAIL PROTECTED] > web : www.e-horizon.se > phone : +46 8 524 201 80 > mobile: +46 708 85 23 35 > ____________________________________ > > _______________________________________________ > 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
