Adam Roach wrote:
In 4.5.2, it seems to me to be unwise to allow the notifier to respond 403 to subscriptions within existing dialogs, as that is a significant constriction of the current requirements.In what way? Implementors are still allowed to accept such incoming connections, but one of the key changes I think is necessary in this revision is to free implementors from the morass of coding for dialog sharing -- because MOST PEOPLE GET IT WRONG. I see little value with maintaining backwards "compatibility" with a feature that, by and large, wasn't compatible between multiple implementations in the first place.
I'd be interested in hearing in what ways "most people" get it wrong. Getting the common cases of dialog sharing right isn't so difficult. I expect that "most people" get corner cases wrong in lots of things. This only frees implementors if: - they are capable of creating their own gruus without registration - or they ONLY work with registrars that support GRUU. - and they only interact with other UAs that support 3265bis.Notably, any phone that *might* be attached to a registrar that doesn't support GRUU will need to support dialog sharing. And any UA that might establish a dialog with somebody that doesn't implement 3265bis should be prepared to have the other end initiate dialog sharing.
I guess the question is whether the bis should indicate what should be done to maintain backward compatibility with 3265, or if that should simply be left for implementors to figure out for themselves. I can see the merit in leaving the old cruft out so that it *eventually* goes away.
Thanks, Paul