"A" must honor BYE and send 200 OK. Proxy "S" can send 481 or 403.
Regards, Kamal Cisco, Bangalore India -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Vishal Agrawal Sent: Thursday, December 10, 2009 3:34 AM To: [email protected]; [email protected] Subject: [Sip-implementors] Glare condition with BYE and re-INVITE requests Hi, Assume that phone "A" issues a re-INVITE request to the SIP server "S" and at the same time "S" issues a BYE request to "A". Is it valid for "A" to send a 491 response to this BYE request from "S"? The SIP INVITE dialog is for a point to point media session. Here is the quote from the Section 15.1.2 in RFC 3261 - "A UAS core receiving a BYE request for an existing dialog MUST follow the procedures of Section 12.2.2 to process the request. Once done, the UAS SHOULD terminate the session (and therefore stop sending and listening for media). The only case where it can elect not to are multicast sessions, where participation is possible even if the other participant in the dialog has terminated its involvement in the session. Whether or not it ends its participation on the session, the UAS core MUST generate a 2xx response to the BYE, and MUST pass that to the server transaction for transmission." >From the above, my understanding is that "A" must send a 200 OK >response for this BYE request regardless of it terminating the SIP session or not, is this understanding correct? >From reading the sections 14.2 and 21.4.27, it seems RFC 3261 mentions >491 response for INVITE requests only in glare conditions. Is it valid and a good idea to send a 491 response for the BYE request when a re-INVITE client transaction is pending? Lastly - "UAS SHOULD terminate the session" - why is this requirement at SHOULD level? If the far-end "S" wants to terminate the session and has sent a BYE request, mustn't "A" terminate the session and expect a 487 from "S" for its re-INVITE? Thanks, Vishal _______________________________________________ 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
