Hello Casey, As per RFC 3261 section 9.2
If the UAS did not find a matching transaction for the CANCEL according to UAS first processes the CANCEL request, it SHOULD respond to the CANCEL with a 481 (Call Leg/Transaction Does Not Exist). If the transaction for the original request still exists, the behavior of the UAS on receiving a CANCEL request depends on whether it has already sent a final response for the original request. If it has, the CANCEL request has no effect on the processing of the original request, no effect on any session state, and no effect on the responses generated for the original request. If the UAS has not issued a final response for the original request, its behavior depends on the method of the original request. If the original request was an INVITE, the UAS SHOULD immediately respond to the INVITE with a 487 (Request Terminated). A CANCEL request has no impact on the processing of transactions with any other method defined in this specification. In your case the UAS SHOULD immediately respond to the INVITE with a 487 "Request Terminated" message. Regards, Satish On Fri, Sep 13, 2013 at 3:37 PM, Guan Xsun <guanxian...@gmail.com> wrote: > heHi, > A SIP client create a dialog by sending INVITE and then will cancel it. > Whether the dialog can be finished when the dialog receive the 200 OK > from cancel or it needs receive the 487 message ? > > Best Regards! > Casey > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > -- Thanks & Regards Satish Agrawal New Delhi-24. _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
