Brett is certainly right that a proxy could recover.
I now have a question: Once the refreshing INVITE (or UPDATE or whatever) has reached it's limit of retransmission, what should it do? Should it retransmit the INVITE every 64*T1 milliseconds and hope for a response? And if no response is received, then send the BYE "slightly before session expiration". >Let us assume the session interval is 1800 seconds, >So I should send re-INVITE after 900 seconds from call establishment, >If I don't get any response for the re-INVITE sent then I should send the >BYE after 1790 seconds from call establishment. So, assuming Ravi's figures are correct, in the above case we keep the session up for approx. 900 seconds. So the call will finally be terminated after 15 minutes? > -----Original Message----- > From: Brett Tate [mailto:[EMAIL PROTECTED] > Sent: 10 September 2003 14:43 > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED] > Subject: RE: [Sip-implementors] A Query about session-timer > > > > However, if you are the refresher > > (which is what your question refers to) > > then it is not so clear (and maybe just > > plain wrong). Surely if one has sent > > the INVITE and its retransmissions and > > no response was received, then it must > > be that the other end has experienced a > > serious error. > > Not true. A proxy or something in the > signaling path might be down or undergoing > a restart. > > > And once the retransmission limit is > > reached then the call should be > > terminated. I can't see any point in > > waiting any longer. > > The proxy might recover so the session > could be refreshed. > > One could honor the expiration value > instead of tearing down the session at > half the expiration value. > > However rfc3261 section 12.2.1 > mentions that the 408 SHOULD trigger > a termination of the dialog. To avoid > debating the 408 issue again and to avoid > a SHOULD conflict, maybe the timer draft to > reflect the rfc3261 SHOULD text. > > _______________________________________________ > 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
