From: "raghuram gangi" <[EMAIL PROTECTED]> When a UE sends a Target Refresh Request, should UE continue to listen on the Old Contact until it receives 1XX ( except 100 Trying ) or 2XX Responses?
The answer is complex. If the other UE sends a non-2xx final response, the request has been rejected, and by definition, will not cause a target refresh either. There is also the possibility that other requests or responses are still in transit. So, to be safe: Once the UE has sent the target refresh request, it must listen on both addresses -- the old address for responses to the request (which are routed by the Via's on the request, and not affected by the target refresh), and both addresses for requests by the other UE. If the UE receives a failure response, it may immediately stop listening on the new address, because the other UE has not accepted the target refresh, and hence cannot have changed its target. If the UE receives a success response, it must continue listening on the new address, and on the old address for as long as requests can be in transit (which is two or three minutes, if I remember correctly). If the UE receives an implicit 408 response because the request timed out, it is in a quandry, as the target refresh may have been seen and acted on by the other UE, or it may not have. I expect that most UE's listen on all IP interfaces that are available on their host platform, and so they do not actively manage which addresses they can receive messages on. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
