Hi Del, I feel the INVITE request may be passed through proxy and proxy inturn might have forked the INVITE request.
So when CANCEL request (without to-tag) is sent by UAC, this single CANCEL request will cater to clear all the forked calls. CANCEL request (with to-tag) will only be able to clear a particular dialog. If anyone has any comment for the logic above, please do comment. Thanks, Sunil -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Del Stevens Sent: Monday, April 02, 2007 7:32 PM To: [email protected] Subject: [Sip-implementors] CANCEL with/without 1xx To tag I have not seen anywhere confirmation one way or another on this topic. F1 A ----- INVITE -------> B F2 A <----- 183 ------------ B F3 A ----- CANCEL ----> B F1 contains From tag. F2 contains From tag and To tag The question is: Is the F3 CANCEL required to send both From and To tags? RFC 3261 Section 9.1 states... The following procedures are used to construct a CANCEL request. The Request-URI, Call-ID, To, the numeric part of CSeq, and From header fields in the CANCEL request MUST be identical to those in the request being cancelled, including tags. Thanks. Del Stevens CopperCom <www.coppercom.com> _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors "This email message and any attachments are confidential information of Starent Networks, Corp. The information transmitted may not be used to create or change any contractual obligations of Starent Networks, Corp. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this e-mail and its attachments by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify the sender immediately -- by replying to this message or by sending an email to [EMAIL PROTECTED] -- and destroy all copies of this message and any attachments without reading or disclosing their contents. Thank you." _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
