[jdev] XMPP vs SIMPLE

[aragalo at cs.uct.ac.za]

I am working on a masters project that compares XMPP and SIMPLE for the
conveyance of presence information. My question is very specific:

In a typical presence scenario (involving a Presentity, a Watcher and a
Presence Server), the SIMPLE protocol specifies that when a Presentity
sends presence information to the Presence Server, the Presence Server
sends a response to the Presentity to confirm the receipt of the presence
information. Similarly, when the Presence Server forwards an update of a
Presentity's presence information to all the subscribed Watchers, the
Watchers must confirm the receipt of this information by sending a
confirmation message back to the Presence Server. These confirmation
messages are useful in a scenario whereby multiple hops may be involved in
the transmission of information between the client and server side of a
presence system. This is because some of these hops may involve unreliable
transport (UDP). Therefore even if a presence system is involves opening
TCP connections on both the client and server sides, multiple hops
introduce unreliability into the delivery of presence information. SIMPLE
caters for this by confirmation messages. XMPP, however, does not specify
that confirmations for the receipt of information should be sent. In
implementing an XMPP presence system in a multi-hop scenario should a
developer incorporate confirmation messages into the XMPP application?