A dialog is established on the UAS side on sending 200 OK to the INVITE. So, it should be prepared to receive a Re-INVITE before it receives the ACK.
So, I would expect to honor the Re-INVITE. Alternatively, the implementation can drop the Re-INVITE and wait for the ACK to arrive. Also the Re-INVITE will be retransmitted so that it can be handled at that time. Either way, if the ACK is never received for the original INVITE, the call will be disconnected by sending BYE. Thanks, Neel -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Stephen Paterson Sent: Wednesday, November 01, 2006 10:41 AM To: SIP Implementors (E-mail) Subject: [Sip-implementors] Handling a of re-INVITE before initial ACK isreceived Hi all, Section 14.2 of RFC 3261 states: A UAS that receives a second INVITE before it sends the final response to a first INVITE with a lower CSeq sequence number on the same dialog MUST return a 500 (Server Internal Error) response to the second INVITE and MUST include a Retry-After header field with a randomly chosen value of between 0 and 10 seconds. A UAS that receives an INVITE on a dialog while an INVITE it had sent on that dialog is in progress MUST return a 491 (Request Pending) response to the received INVITE. Question is: What should the UAS do if it receives a re-INVITE after it has sent the final response but before it receives the ACK for the initial INVITE? This situation doesn't fit either of the above two scenarios and I can't find anything elsewhere in the RFC to help. Currently our stack ignores the second INVITE but my gut feeling is there should be some sort of 4xx response, possibly containing a Retry-After header. Regards Steve Steve Paterson Software Engineer Aculab Tel: +44 (0) 1908 273866 Fax: +44 (0) 1908 273801 Email: mailto:[EMAIL PROTECTED] Website: http://www.aculab.com _______________________________________________ Sip-implementors mailing list Sip-implementors@cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
