> > If an appearance number has been explicitly > > seized using PUBLISH, it would seem desirable > > to include the appearance number within the > > INVITE to reduce confusion. Without such > > explicit indication, the Appearance Agents's > > involvement with the outbound INVITE would be > > required to make assumptions to correlate the > > successful PUBLISH to INVITE. > > Well, I think loose coupling between the > appearance agent and the proxy is actually a > good thing for the design. And architects can > always tightly couple them without any problems. > > Here's how I look at it. The PUBLISH to seize > the appearance is just that - it just reserves > it for a particular UA in the appearance group. > At that point, it should not be tied to any > specific call - it is up to the UA what to do > with the appearance. Shortly after, the INVITE > is sent - at this point, there is not tight > coupling either, but there is no need for it. > As soon as an early dialog is created with a 18x > or a dialog with a 2xx, then the UA sends > another PUBLISH. At this point the appearance > is correlated with the dialog, and this is when > it needs to be. The appearance agent shares > this information with the other UAs in the > group. Unless there is some requirement that we > haven't discussed, I think this works.
For a line-seize call setup, the appearance agent would be sending some useless notifies associated with the INVITE until the caller PUBLISHes that the INVITE is associated with the seized appearance. More specifically, appearance agent may send NOTIFY without appearance for the 18x dialog and then have to send another one when the caller decides to PUBLISH that the dialog is associated with the seized appearance. I'd prefer the caller be able to communicate such information within the outgoing INVITE. Similarly for origination situation without PUBLISH line-seize, section 5.3 indicates appearance agent selects the appearance. If there is an allocated seized appearance (obtained from PUBLISH) without corresponding INVITE, is appearance agent supposed to allocate a non seized appearance or assume INVITE corresponds to the seized appearance? Thanks, Brett _______________________________________________ BLISS mailing list [email protected] https://www.ietf.org/mailman/listinfo/bliss
