Hello,
I've already posted message on this topic, but some questions remain unanswered.
 
My concerns are bout the pa module (presence).
 
 
* Does it support RFC3857 to allow authorization management of subscriptions?
* Any ideas if the presence server can be easily distributed on several machines?
    - What kind of database is used (to ensure having up-to-date data on each server) ?
    - How to determine which server sends the status change's notification to users?
* How can one estimate the required bandwidth (5000 online users, with avg 40 users per contact list, is likely to generate many NOTIFY message)
* Is it possible to performs computation before proceeding (to check account credit before giving access to a service)

Regards,
 
Luba Vincent