One can argue that Call-id:CSeq-No or from-tag:CSeq-No may > also be used but using branch parameter is the most simple approach. ------ Not sure on this one. In case of Forking, all above parameters could potentially be same. Via is surely different among forking INVITE. This helps in identifying to which CANCEL should be sent.
Vipul Rastogi Engineer, Business Management Team Telecommunication Network Business Samsung Electronics CO, LTD Suwon P.O.BOX 105, 416 Korea 442-600 MO 010-9530-0354 ----- Original Message ----- From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> To: "Serhad Doken (serhad)" <[EMAIL PROTECTED]> Cc: <sip-implementors@lists.cs.columbia.edu> Sent: Thursday, November 22, 2007 9:55 AM Subject: Re: [Sip-implementors] Branch param for CANCEL message > > Branch is used to match CANCEL and ACK to the transaction being CANCELed > or ACKed. One can argue that Call-id:CSeq-No or from-tag:CSeq-No may > also be used but using branch parameter is the most simple approach. > > Serhad Doken (serhad) wrote: >> CANCEL and ACK for non-2xx responses will have the same branch id as the >> INVITE so they won't have a unique branch-id whereas INVITE and other >> requests will always have unique branch ids. I don't see a contradiction >> in the text. >> >> Serhad >> >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of >> vinodh kumar >> Sent: Wednesday, November 21, 2007 6:51 PM >> To: sip-implementors@lists.cs.columbia.edu >> Subject: [Sip-implementors] Branch param for CANCEL message >> >> >> >> Hi all, >> >> I have a query regarding branch parameter in via tag. >> >> RFC says >> >> The branch parameter value MUST be unique across space and time for all >> requests sent by the UA. The exceptions to this rule are CANCEL and ACK >> for non-2xx responses. As discussed below, a CANCEL request will have >> the same value of the branch parameter as the request it cancels. As >> discussed in Section 17.1.1.3, an ACK for a non-2xx response will also >> have the same branch ID as the INVITE whose response it acknowledges. >> >> I am bit confused about the statement. It says CANCL and ACK are >> exception for the rule Branch parameter must be unique. But in next line >> it says CANCL request will have same branch parameter as that of request >> it cancels. >> >> Whats the conclusion on this. Please clarify. >> >> Regards, >> Vinodh >> >> >> >> The information contained in this electronic message and any attachments >> to this message are intended for the exclusive use of the addressee(s) >> and may contain proprietary, confidential or privileged information. If >> you are not the intended recipient, you should not disseminate, >> distribute or copy this e-mail. Please notify the sender immediately and >> destroy all copies of this message and any attachments. >> >> WARNING: Computer viruses can be transmitted via email. The recipient >> should check this email and any attachments for the presence of viruses. >> The company accepts no liability for any damage caused by any virus >> transmitted by this email. >> >> www.wipro.com >> _______________________________________________ >> Sip-implementors mailing list >> Sip-implementors@lists.cs.columbia.edu >> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >> >> _______________________________________________ >> Sip-implementors mailing list >> Sip-implementors@lists.cs.columbia.edu >> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >> >> >> >> > > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
