Hi Hadriel, I guess Gonzalo will provide his summary soon, but I don't think there is currently a disagreement regarding pre-conditions. You call them "conditional offers", Gao calls them "notifications", but that's just wording... :) I think the one of the main issues at the moment is what happens after preconditions have been met on both sides: 1) Is the change now commited/in-use, and a re-INVITE failure would not change that? <----- "in-use" alternative OR 2) Would a re-INVITE failure cause a fallback (this is what is meant by "late commitment")? <---- "late commitment" alternative If preconditions have NOT been met, and the re-INVITE fails, I think most agree that there will be a rollback to the "last committed state". Gao's draft also talk about other changes which would not be considered as "real" SDP offers, for example if you reduce codecs. But, at least I strongly prefer NOT to go into such details, because that would for sure cause interop issues. I am not sure what Gao's view on that is at the moment, though? Regarding the race condition, I think we can avoid that with some BCP- and guidance text. Regards, Christer -----Original Message----- From: Hadriel Kaplan [mailto:HKaplan@xxxxxxxxxxxxxx] Sent: Saturday, February 28, 2009 5:26 PM To: Christer Holmberg; Gonzalo Camarillo; sipping Subject: Summary of Closing the offer/answer rollback issue? Is there an email in this long thread that summarizes the issues? It's impossible to follow this thread. :) I'm not clear on what the issues are with pre-conditions that make failed offers concept break. To me, pre-conditions are basically not real SDP offers; they're conditional offers. Until the *all* the conditions are met, it's not "committed". You continue using the last committed state. I know there are race conditions, but considering how rare pre-conditions are in the real world (especially in re-Invite's), that I'm having trouble imagining why we should care about corner cases of such. Regardless, I vote for any fixing that needs to happen because of pre-conditions should be around changing pre-condition logic, even if it means completely re-writing how pre-conditions works - don't change normal SIP or SDP. (not that anyone is proposing it, I just can't tell form this thread) Re-Invites and SDP offer/answer have so many interop issues in the wild even without pre-conditions, that this whole thread scares me. :( -hadriel _______________________________________________ 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
