Anil, The presence of same call-id, cseq, branch-id in vias should be enough to indicate that it is a retransmitted INVITE rather than a forked INVITE or a new INVITE.
On receiving an INVITE on UAS typically the "software" looks up the CALLID to check if there is a call(dialog) with that CALLID. if there is a dialog with that callid, then you look at the from-tag (different from tag should instantly be flagged as an error), branchid, cseq number etc to verify that it is not a forked invite or a re-invite(if to-tag present). Given that it does not meet the above three conditions : it is not a INVITE on an INVALID call, it is not a forked INVITE, it is not a re-INVITE, it is treated as a retransmitted INVITE) On the otherhand, on a stateless proxy such a retransmitted INVITE needs to be forwarded towards the UAS since it does not have the context to interpret the message. thanks Arun Punj ViPr Principal Engineer Broadband Routing & Switching Marconi 3000 Marconi Drive Warrendale, PA 15086 Phone: 724-742-7583 [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Anil > Bollineni > Sent: Thursday, May 26, 2005 6:29 PM > To: [email protected]; [email protected] > Subject: [Sip-implementors] About Invite Server transaction > > > Hi, > > Assume 100, 200 responses are sent from UAS to client, and > they are lost. Then INVITE is retransmitted to UAS. As soon > as UAS send > 200 OK it destroys the server transaction. Per UAS, the > dialog state is > already created after sending 200 response. If INVITE is passed to TU > from transport layer, then how this INVITE is been treated as > retransmission of INVITE, since the TU, will not able to match any > existing dialog (since no to-tag in INVITE), and will it > treat as a new > call. Is the assumption correct? Or where in RFC this scenario will be > treated. > > > > Thanks, > > Anil > > _______________________________________________ > 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
