Hi, > 1. the situation of inconsistent media level(perhaps it is impossible) there is a situation we need to clarify regarding how to configure the endpoint's media tools at a given point. However, this is a general issue, not specific to the rollback issue we are discussing here. We discussed this issue a long time ago but clarifying it at this point may be a good idea. The issue is the following: Two endpoints involved in a session perform a successful offer/answer exchange in a re-INVITE or in an UPDATE to change the media parameters. When can the endpoints stop using the old parameters and start using the new parameters? This synchronization-related issue is caused by the fact that signalling and media are only loosely coupled. The typical answer is that the endpoint stops using the old media parameters (e.g., stop listening on the old port) when it starts receiving media with the new parameters. Of course, the endpoint can also implement a timer to cope with delayed media packets using the old parameters. When preconditions are used, the period where the endpoint acting as the UAC needs to be prepared to receive media with both the old and the new parameters is longer because once its preconditions are met, the UAS may take a while to meet its own preconditions. In any case, the solution is the same. The UAC stops using the old configuration when it starts receiving media with the new configuration. The UAC can also request confirmation of the preconditions so that the UAS lets the UAC know when In any case, as you can see, this is a general SIP issue on signalling-media synchronization, not specific to the rollback issue we are discussing here. Cheers, Gonzalo _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP
