Hi, Thank you for your responses. It seems that RFC 3261 has the following text which confirms Paul's opinion that a race condition between BYE and re-INVITE is not a glare...
"RFC 2543 was silent on whether a UA could initiate a new transaction to a peer while another was in progress. That is now specified here. It is allowed for non-INVITE requests, disallowed for INVITE." To summarize what I read (this thread and RFC 3261 and 5407) A must send 200 OK for BYE request to S and S must send a 481 response to re-INVITE request and the session should (or must?) terminate between A and S. -Vishal On Thu, Dec 10, 2009 at 12:09 AM, Dushyant Dhalia < [email protected]> wrote: > A to send 200 OK of Bye and ACK for 481 (Re-INV). > S to send 481. > > See section 3.2.2 of RFC 5407. > > Regards, > Dushyant P S Dhalia > Rancore Technologies, > Gurgaon, INDIA > > Vishal Agrawal wrote: > > 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 > > > -- > "When work is a pleasure, life is a joy! When work is duty, life is slavery." > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
