Hi, Yes the Proxy can stop re-transmitting the Request after sending a 408 towards the caller(A). For some reason if the Invite somehow manages to reach B after 25 secs (which is highly unlikely) it may respond with 18x/200. The proxy can statelessly forward these responses to A and let A deal with it by either sending ACK followed by BYE (for 200) or CANCEL or just ignore it. Ignoring will result in retransmission of 200 OK.
Question) If CANCEL is received at a PROXY for which it does not have a corresponding transaction does it relay it. If it has to relay it and does SRV/DNS on the Req URI again it may end up with a different Destination for Cancel Kasturi -----Original Message----- From: Andreas Byström [mailto:[EMAIL PROTECTED] Sent: Monday, December 18, 2006 4:58 PM To: [email protected] Subject: [Sip-implementors] Expires timer triggers before Timer B, what to do? Hi, my problem is about a scenario where A calls B using "application server/B2BUA" P1. A -> Invite B -> P1 -> Invite [EMAIL PROTECTED], Expires=25 -> B - P1 only want this call to be ringing for 25 seconds without final response so it includes a Expires header with value 25 in the outgoing invite to B - B is not powered so nothing will answer any provisional or final response to the invite - Invite is retransmitted several times 25 seconds after sending the first Invite to B, P1 will consider the call as "ring timeout" and will send a 408 to A. On the B side however, how should it do? Timer B has not fired yet on this side, and when reading the client invite transaction state in RFC3261 17.1.1.3 it looks to me as P1 needs to continue to retransmit the Invite to B until Timer B fires, to get to Terminated state. Is this correct? Or is it ok for P1 to stop the retransmit since it has taken down A side of the call there is no point of continue to retransmit (it will be bad if B now answers the reinivte that was sent after Expires timer has triggered on P1) Basicly, what to do when Expires timer triggers before Timer B? If the case was that P1 have got 100 trying from B, P1 would just have sent a Cancl but that is not allowed now when there has been no response at all Appreciate any help on this Regards, // Andreas _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
