Hello,

We would like to use SER in a production environment and provide
presence support to at least 5000 *online* users through a publicly
available service.

We are particularly worried about scalability.

* How stable is the presence module?

* Does it support RFC3857 to allow authorization management of
subscriptions?

* For such a big number of users, do we need several computers running
SER?

* If so, how can we ensure that all SER servers have the required
information to be able to send status changes to all users? Is that
stored in a MySQL DB and if so, how is it determined which SER server
sends the NOTIFY on state changes to all users having the user whose
state changed in their list?

* Are there bandwidth estimations? I have the feeling that 5000 online
users will generate many NOTIFY messages due to presence changes. 

* Is it possible to prevent MESSAGE requests to be sent following some
piece of information found in the database? We would like to connect SER
to a SMS service, and prevent users to send SMS'es when their credit is
not enough. That supposes some computation in the ser.cfg file, is that
possible?

Greetings,

Luba Vincent