[SIPForum-discussion] SIP Presence

[steve parrish]

Hello everyone,

I have a question related to authorizing subscribers (watchers) in the SIP
Presence model.

I have read several pertinent RFC's and draft's related to Presence.  I clearly
see and understand how event packages are used for watchers to subscribe to a
presentity's presence state and also how UA's can subscribe to watcher
information via the "presence.winfo" package.

I however, do not quite understand how a presentity can authorize (allow or
deny) a watchers request for a presence subscription.

Is this accomplished via mechanisms defined outside of SIP?

Is XCAP used to authorize subscribers? Are there other protocols\methods used
to authorize subscribers?

Can anyone lead me to documentation that directly discusses this issue?

Any help would be much appreciated

-Steve