The CANCEL MUST have the same to-tag as the INVITE it is cancelling. If the INVITE had a to-tag, the CANCEL MUST have the same to-tag.
If the INVITE did not have a to-tag, the CANCEL MUST NOT have a to-tag. Section 9.1 of RFC 3261 is very clear on this: 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. With an initial INVITE, you cannot send CANCEL for an early dialog by including the to-tag from a 1xx response. If you wish to cancel/terminate a specific early dialog, you use BYE. See section 15 of RFC 3261 for details. cheers, (-:bob Robert F. Penfield Chief Software Architect Acme Packet, Inc. 71 Third Avenue Burlington, MA 01803 [EMAIL PROTECTED] ----- Original Message ----- From: "Manjunath Warad" <[EMAIL PROTECTED]> To: "'Nataraju A B'" <[EMAIL PROTECTED]>; "'Banibrata Dutta'" <[EMAIL PROTECTED]>; "'Sip-Implementors (E-mail)'" <[email protected]> Sent: Thursday, December 15, 2005 6:24 AM Subject: Re: [Sip-implementors] CANCEL request in the INVITE initiated Dialog > Hi > One more reason why To tag is optional in Cancel, since Cancel will > be matched with the transaction of INVITE and for the transaction match To > tag is not required, rather it matches with Branch-Id. Branch-Id being > unique will identify which INVITE it is cancelling. > > Regards, > Manju > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Nataraju A > B > Sent: Thursday, December 15, 2005 4:39 PM > To: 'Banibrata Dutta'; 'Sip-Implementors (E-mail)' > Subject: Re: [Sip-implementors] CANCEL request in the INVITE initiated > Dialog > > > > > Thanks & Regards, > Nataraju A.B. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Banibrata > Dutta > Sent: Thursday, December 15, 2005 3:02 PM > To: Sip-Implementors (E-mail) > Subject: [Sip-implementors] CANCEL request in the INVITE initiated Dialog > > hi, > > a CANCEL sent for an INVITE will in the INVITE initiated Dialog. So should > the CANCEL request have both the From & To tags, or just the From tag ? I > believe that both should be sent, because the full Dialog related > information could be available from the received provisional response > (s.a. > 182 or 183). > > > [ABN] the CANCEL request may optionally contain the to-tag. Since 100 > Trying > response may not carry the to-tag. If some 1xx response received which > carried to-tag, this tag might be put in CANCEL request, but none of the > intermediate entities or servers mandate the presence of to-tag in CANCEL > request processing...... > > thanks for any clarification. > > regards, > bdutta > _______________________________________________ > 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 > > _______________________________________________ > 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
