23.1413GPPArchitecture and functional descriptionPresence serviceRelease 17TS
Figure A.1-1 illustrates the message flow for user A requesting presence information for user B in a different network.
Figure A.1-1: Presence enquiry message flow
1. The A party sends a presence enquiry to Watcher Application A (WA-A). The A party identifies B by B’s address (e.g. MSISDN or URI). The enquiry can be of various types, e.g.:
a) "tell me the current state of B"
b) "tell me all state changes of user B for the next x hours"
c) "tell me when B next changes state"
d) "stop telling me about B"
2. Watcher Application A ‘authenticates’ A and checks their credit status (details of authentication and credit status are outside scope of this message flow)
3. Watcher Application A sends a "Presence enquiry for B" message to Watcher Presence Proxy.
4. The Watcher Presence Proxy derives B’s network name from B’s address (details of how this is derived is outside the scope of this message flow).
5. The Watcher Presence Proxy sends a "Presence enquiry for B" message to B’s network’s Presentity Presence Proxy.
NOTE: Authentication may be necessary between A and B party networks in line with techniques used in other instances of inter operator message flow; precise details are outside the scope of this message flow.
6. The Presentity Presence Proxy derives the address of B’s Presence Server
7. B’s network Presentity Presence Proxy sends "Presence enquiry for B" message to B’s Presence Server.
8. B’s Presence Server processes the presence enquiry request (e.g. check A is one of B’s buddy’s and B still wants A to watch him/her).
9. B’s Presence Server raises charge record for A against A’s network (precise details are for further study)
10. B’s Presence Server sends B’s status back to Watcher Application A in Originating PLMN (may be returned via Presentity Presence Proxy and Watcher Presence Proxy).
11. Watcher application returns B’s presence to use A.
NOTE 1: Steps 10 and 11 are repeated as necessary if B party has been requested to provide regular presence updates.
NOTE 2: In the event that the presence enquiry message is "stop telling me about B" steps 8-11 are just an acknowledgement for watcher application A.