I don't think this should be a problem, because: a) "A CANCEL request SHOULD NOT be sent to cancel a request other than INVITE" (bis-09 section 9.1)
b) "If no provisional response has been received, the CANCEL request MUST NOT be sent" (bis-09 section 9.1) c) "the Via header field value MUST contain a branch parameter" and "The branch parameter value MUST be unique across space and time..." (bis-09 section 8.1.1.7) and "A CANCEL request constructed by a client MUST have only a single Via header field value matching the top Via value in the request being cancelled" (bis-09 section 9.1). So, the UAS would have to send a 1xx response for the INFO (but it is suppose to generate a final response in a timely manner), and in any event, the Via should match the INFO request. cheers, (-:bob Robert F. Penfield Chief Software Architect Acme Packet, Inc. 130 New Boston Street Woburn, MA 01801 [EMAIL PROTECTED] ----- Original Message ----- From: "salman basit" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Friday, May 10, 2002 6:44 AM Subject: [Sip-implementors] RE: Cancel for Info (Vijeth D) > Hi, > There are two scenarios to consider > > a)If UA1 does not receive any provisional response, it should not send any > Request. Thus it shouldnt send CANCEL or INFO(Section 13.2.1 line: 2116 > bis-09) > > b) > UA1<---1xx Response---UA2 > UA1--->CANCEL--UA2 > UA1<---200 INVITE-----UA2 > If UA1 receives any provisional response and sends CANCEL, and receives a > 200 Response as shown above, it MAY send a BYE(Section 15 bis-09 line: 2370) > > >How will UA2 know whether the CANCEL was for INFO or for INVITE ? > Through CSeq No. INFO will have an incremented CSeq No > > Salman Abdul Baset > Design Engineer > Avaz Networks > [EMAIL PROTECTED] > > > >1. Cancel for Info (Vijeth D) > > >Hi, > > Consider the following scenario. > > UA1 sends Invite to UA2 > > UA2 sends 200 OK but before it reaches UA1, UA1 generates > >CANCEL. ( 200 and CANCEL "on the wire" ). > >Now UA1 ACKS UA2 and sends an INFO. > >If the INFO reaches UA2 and then the CANCEL arrives. > >How will UA2 know whether the CANCEL was for INFO or for INVITE ? > > >Thanks and Regards, > >Vijeth > > > _______________________________________________ > 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
