The IMS original dialog-id is used by the S-CSCF to correlate an INVITE from an App Server to the INVITE previously sent to the AppServer and thus to identify the position in the IFC processing sequence, to resume IFC application.
Is it valid for the App Server to use the original dialog-id in the following situation, in the new INVITE it sends to the S-CSCF - 1. AS recurses on a 3xx and sends an INVITE to the S-CSCF using the contact in the 3xx. 2. AS handles a failure response and sends a new INVITE to the S-CSCF to try another destination Uri (serially attempting different registered contacts). Once IFC processing has been completed or prematurely terminated by a redirection, the S-CSCF has no use for the original dialog-Id. The AS can always initiate a new call on behalf of the user without an original dialog-id and maintain a local correlation between the original call and the new call, as a B2BUA. It is not clear from the specs what should be the behavior of the S-CSCF and AS. Perhaps it is discussed somewhere and any pointers will be useful. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
