Hi Rakesh, your first question is easy to understand.
RFC 3261, 9 Cancelling a request "If no provisional response has been received, the CANCEL request MUST NOT be sent;" In my opinion it is a correct behaviour to retransmit INVITEs (TimerA) and to wait until the retransmission control timer (Timer B) expires. Because it could still happen that you will receive a 200 OK for the INVITE which must be answered with an ACK and a BYE if you are not interested in building up the call. If you receive a provisional response you should try to cancel the action by sending out a CANCEL. Your other question is a little more tricky. Normally only a user agent should create and send 487 Request Terminated. I am not a IMS specialist but I have heard that IMS uses a lot of B2B SIP Proxies which are able to generate 487 Request Terminated. It depends of the kind of the CSCF. Regards, Markus Rakesh Hooda wrote: > I am facing an issue of retransmission of INVITE when UE is not sending any > response of INVITE Request. In this case S-CSCF sends CANCEL towards P-CSCF > whereas P-CSCF is retransmitting INVITE towards UE as no provisional message > received from UE. > > After receiving CANCEL, P-CSCF sends 200 OK for this request but cann't stop > retransmission timer running at P-CSCF. As a result, retransmission is still > going on towards UE whereas a Request is cancelled by S-CSCF. > > Can u pls. let me know... is it correct behavior or not. > > As per my understanding correct behavior should be - P-CSCF should stop the > retransmission timer as UAC cancelled the request so there is no need to > process > request. > > One more quesy - In this case, can P-CSCF generate 487 Request Terminated to > end > the transaction towards S-CSCF ???? > > As per RFC 3261: > A TU that creates a client transaction can also cancel it. > When a client cancels a transaction, *it requests that the server stop > further processing, revert to the state that existed before the > transaction was initiated*, and generate a specific error response to > that transaction. > > Can u pls. explain behavior of UAS (P-CSCF in this case)???? > > Thanks in advance... > Regards > Rakesh Hooda > "None of us is as smart as all of us" > " DISCLAIMER: This message is proprietary to Flextronics Software Systems > Limited (FSS) and is intended solely for the use of the individual to whom it > is > addressed. It may contain privileged or confidential information and should > not > be circulated or used for any purpose other than for what it is intended. If > you > have received this message in error, please notify the originator > immediately. > If you are not the intended recipient, you are notified that you are strictly > prohibited from using, copying, altering, or disclosing the contents of this > message. FSS accepts no responsibility for loss or damage arising from the > use > of the information transmitted by this email including damage from virus." > > > ------------------------------------------------------------------------ > > _______________________________________________ > 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
