Presence and IntComm WG

[Jamey Hicks <>]

- UA's register

- UA's subscribe to event package presence.winfo (type
 application/watcherinfo+xml) on their own SIP URI

 - the presence agent automatically allows a UA to subscribe to itself

- UAs (watchers) subscribe to the presence event package buddies' SIP URI's

 - If the watcher is authorized to subscribe to that event package,
   then the PA ACKS and sends a NOTIFY and continues to send NOTIFY
   messages when the users's state changes

 - A watcherinfo NOTIFY is sent to any presence.winfo subscribe on
   the user's URI (typically only the user's UA)

- upon receipt of presence.winfo NOTIFY, the UA queries the user
 whether they would like to authorize the watcher to subscribe

- the UA uses xcap to GET and PUT the watcherinfo document on the PA

- when the PA receives an xcap update, it examines the changed portion
 of the document and updates the status of any pending subscriptions

- the PA aggregates presence data that is sent to it in PUBLISH bodies

- presence event information is shared in xml format 
application/cpim-pidf+xml