> -----Original Message-----
> From: Dean Willis [mailto:[EMAIL PROTECTED]
>
> > the proposal is interesting.
> > However there should be cases where you need to send whatever
> > information in both directions, or cases where when you send an
> > information via Notify you need to receive back some information (e.g.
> > the fact that you receive a 200Ok as answer to the Notify it is not
> > enough).
> > How do you think your proposal should work in those cases ? perhaps
> > with
> > 2 subscription one in each direction?
> >
>
> Yes, although I prefer to think of it (in this example) as each end
> having independently declared a willingness to receive events of the
> given package within the current INVITE-bounded dialog.
>
> It might also be reasonable to envision two different event packages,
> designed to work together.

Yeah, IMHO this shouldn't really be Subscriptions with a capital "S", as in rfc 
3265, with Subscription state and initial Notifies and all.  It's really just 
info-event-package negotiation.


> >>
> >> I would argue that it would be nice to have an extension mechanism
> >> that allows a UA to be asked "Do you support this specific
> >> extension?" without the UA having to encode every extension it
> >> supports in every request it sends, but that's a different issue.
> >
> > that is also something nice. Are you thinking a mechanism like an
> > OPTION
> > that instead to be general just asks for a specific extension?
> >
>
> Yes, I think that would do the trick.
>
> Maybe it's just me, but I find the process of including fully-
> populated Supported and Allow header fields in every request to be a
> bit daunting. Not to mention repetitious, bandwidth and CPU
> consumptive, and so on.

I don't see how OPTIONS helps in reducing any of that.  You'd have to send one 
for every call.  That's more work than a list in a header, no?

> SUBSCRIBE gives us something that will do the job. Without preceding
> contact, we can ask for a subscription to a package, and get an error
> response if it isn't there.

And with this new model, you'd not get the info-event-package in responses for 
the INVITE, and know the same.  Well... you'd know for this INVITE-dialog the 
far end does not support info-event foo.  It may for other INVITE-dialogs, but 
that's arguably more flexible than SUBSCRIBE.


> This is a nice property: It keeps us from having to advertise every
> event package to which we might possibly accept a subscription in
> every message we send.

We're only talking about event packages which make sense for INVITE-dialog 
piggy-backing.  This wouldn't apply to things like presence, reg-event, etc.  
Although I'm not sure how that would be documentable, other than defining 
something new and distinct from rfc3265 event packages.

-hadriel


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