28 Mar
2011
28 Mar
'11
2:19 p.m.
2011/3/28 Olle E. Johansson <oej(a)edvina.net>et>:
- In SIP you can send a Subscribe with Expires:0 to
"query" the server about the current state of a URI.
- In XMPP, the server doesn't have a state for anything. It's just a message
router.
This is not entirely true. In XMPP basic presence ("online", "away",
text message as "I'm at home") is sent as individual messages the
server routes to the watchers. But other more modern features (as user
avatar/image) use PUB-SUB mechanism, so the watcher must subscribe to
a specific user for the watched user.
--
Iñaki Baz Castillo
<ibc(a)aliax.net>