> From: pranab sahoo [pranabsahoog...@gmail.com] > > suppose A calls B.B's phone start ringing,B did not recieve the > call.Finally B's phone stops ringing after some time.So what will be > the error response will go from B to A?
If B's phone decides that the call has rung long enough, or the time specified in the Expires header has passed, B's phone will respond with 487. See RFC 3261, section 13.3.1, item 1: 1. If the request is an INVITE that contains an Expires header field, the UAS core sets a timer for the number of seconds indicated in the header field value. When the timer fires, the invitation is considered to be expired. If the invitation expires before the UAS has generated a final response, a 487 (Request Terminated) response SHOULD be generated. More commonly, the expiration time is enforced by a proxy which sends an INVITE to B's phone, and when the expiration time expires, the proxy sends a CANCEL to B's phone. Upon receiving the CANCEL, B's phone gives a 487 response to the INVITE. (And a 200 response to the CANCEL.) Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors