The INVITE transaction must still complete independent of the CANCEL. So the proxy would continue to re-transmit the INVITE. If the proxy does receive a provisional response, it would then stop retransmissions and send the CANCEL down stream. If timer B fired, it would send a 408 response to the INVITE.
Note that the proxy should respond to the CANCEL with 200 OK when it receives it since the INVITE transaction is in progress. cheers, (-:bob -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Klaus Darilion Sent: Friday, March 07, 2008 4:11 AM To: [email protected] Subject: [Sip-implementors] CANCEL retransmisson question of no provisional response! Hi! Could someone help me please with this question. Scenario: A transaction-stateful proxy forwards the INVITE request. The proxy does not receive a provisional response, thus starts retransmissions. Now, the caller CANCELs the call. How is the proxy supposed to handle this? Does the proxy still have to retransmit the INVITE or can it stop retransmitting the INVITE? From logical point of view I would think that the proxy should stop the retransmissions, but from Figure 5 in RFC 3261 it looks like the only way to come from "Calling" state to "Terminated" state is waiting for Timer B fires (as there is no provisional response yet). thanks klaus _______________________________________________ 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
