Hi Joegen, >>I have also seen UAS silently discarding CANCELs without to-tag if it comes in early >>dialog state. This is wrong because the spec says that CANCEL MUST have all the parameters identical to those being cancelling including tags.
The only case I can see where there is a To-tag in CANCEL is : In a re-Invite request having the to-tag,the CANCEL MUST also have a to-tag. HTH, Sreeram. ---- Sreeram Kanumuri [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, November 20, 2007 11:54 AM To: sip-implementors@lists.cs.columbia.edu Subject: [Sip-implementors] To Tag in CANCEL Hi, As per 9.1 Client Behavior of RFC 3261 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. If my understanding is correct, even if the INVITE being cancelled has already been responded to by a 1xx with a to-tag, the CANCEL will have no to tag. However, I have seen implementations that send a CANCEL with a to-tag if the call is already in early dialog state. I have also seen UAS silently discarding CANCELs without to-tag if it comes in early dialog state. This makes me doubt my original understanding of the RFC. Can anyone shed some light? Joegen _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors 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
