The CANCEL needs to match the original request, including tags (or lack there of). A UAS should reject a CANCEL if it includes a To tag that was not in the original request.
John Hearty Level3 > -----Original Message----- > From: Ken Jordan [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, June 05, 2002 3:32 PM > To: [EMAIL PROTECTED] > Subject: [Sip-implementors] CANCEL for INVITE not sent before > provisional received to avoid race condition - true? > > > > Section 9.1 bis-09 gives the following reason why the CANCEL > should not be > sent by the UAC to the UAS for an INVITE before a provisional > response is > received. > > If it was allowed to send the CANCEL before receiving a > response for the previous request, the server could receive > the CANCEL before the original request. > > I believe another important reason is to handle the race > condition where the > UAS has already sent a response which has not yet been > received by the UAC. > In that case, the UAC would not know the tag value to use in > the To field > and the UAS would reject the CANCEL (not being able to match > it (including > tags) to the INVITE). > > Is this true? Or would the UAS only match against the > original request > (pre-response)? > > Thanks > > Ken > > > > > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
