You are correct. There is no timer for the Proceeding state in an INVITE client transaction. In the case of a User Agent, it is up to the application to decide when to stop waiting, at which point it should send a CANCEL. For example, if the client is a SIP phone, the user would get tired of waiting for the call to complete and hangup which would result in a CANCEL being sent. If the CANCEL works, the client would ultimately receive a 487 or other final response to the INVITE. Section 9.1 does give some guidelines for the case where you never get a final response to the INVITE after sending the CANCEL:
a UAC canceling a request cannot rely on receiving a 487 (Request Terminated) response for the original request, as an RFC 2543- compliant UAS will not generate such a response. If there is no final response for the original request in 64*T1 seconds (T1 is defined in Section 17.1.1.1), the client SHOULD then consider the original transaction cancelled and SHOULD destroy the client transaction handling the original request. For a proxy, it will have set timer C (see section 16.6, bullet 11) when it forwarded the request and upon receipt of a provisional response. Timer C allows a proxy to discard state for an INVITE transaction that never generates a final response. cheers, (-:bob Robert F. Penfield Chief Software Architect Acme Packet, Inc. 130 New Boston Street Woburn, MA 01801 [EMAIL PROTECTED] ----- Original Message ----- From: "Jade Chen Yan" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, January 02, 2003 3:51 AM Subject: [Sip-implementors] no timere for INVITE Client transaction > Hi, List, > > in RFC 3261,17.1.1 > about the INVITE client transaction,if the tranaction comes to the proceeding state, there is no timer for it. If it cannot receive the final response, it will be suspended at this state. .I think timerB will be stop when receivng the 1XX response. > > Can any one tell me whether I am right or not? > > Best Regards, > Jade > > _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
