I guess this is not true just in your example. This can very well happen in a network where a long lost REGISTER finds its way to REGISTRAR. Since the initial request has timed out, it is expected that next request received is n+1 or higher(assuming REGISTER has Cseq n). Since Cseq 'n' does not fit the criteria 500 error response is good enough.
regards Rayees -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Reynolds, Paul Sent: Wednesday, May 02, 2007 6:22 PM To: [email protected] Subject: [Sip-implementors] REGISTER retransmission question Hi, I have a question regarding the correct behavior of a registrar when receiving a late REGISTER retransmission. More specifically, I have come across a UAC that, after successfully registering, sends a subsequent refresh request with the same Call-ID and CSeq values as the original (successful) request. This second request arrives after the initial transaction has timed out, so is not recognized as a retransmission. RFC3261 seems to indicate that this second request should fail: "If the Call-ID value in the existing binding differs from the Call- ID value in the request, the binding MUST be removed if the expiration time is zero and updated otherwise. If they are the same, the registrar compares the CSeq value. If the value is higher than that of the existing binding, it MUST update or remove the binding as above. If not, the update MUST be aborted and the request fails." I believe that this UAC is behaving badly, but still desire to handle this case in compliance with RFC3261. Should I: A) Ignore the second request B) Send a 200 OK, but not update the registration information (expiration, etc) C) Send a 200 OK, AND update the registration D) Send a failure (and if so, what? 400?) Thanks for any and all input, Paul _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ ---------------------------------------------------------------------------------- IMPORTANT The information contained in this e-mail any attachments is intended only for the named recipient and may be privileged or confidential. If you are not the intended recipient, please notify us immediately on +44 (0)1908 425000 and do not disclose, copy, distribute or take any action based on the contents of this e-mail. You should understand and accept that, when communicating with us by e-mail, it is not a totally secure communication medium. We accept no liability for any direct, indirect or consequential loss arising from any action taken in reliance on the information contained in this e-mail and give no warranty or representation as to its accuracy or reliability. DIGITALK has the facility to monitor and read both incoming and outgoing communications by e-mail. In line with industry efforts to reduce the proliferation of Un-Solicited SPAM messages, DIGITALK uses various methods including Reverse-DNS lookups and ban-lists to prevent malicious content reaching our users. This message and any attachments has been scanned for known viruses. However, we would advise you to ensure the content is indeed virus free. We do not, to the extent permitted by law, accept any liability (whether in contract, negligence or otherwise) for any virus infection and/or external compromise of security and/or breach of confidentiality in relation to transmissions sent by e-mail. VAT No: GB 876 3287 81. Reg No: 3080801 Place of Registration: England Registered Office Address: 2 Radian Court, Knowlhill, Milton Keynes ----------------------------------------------------------------------------------" _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
