[Users] Scalability in presence notification

Hi,

I need some advices about a design issue. I'm trying to figure out how to manage my presence information notifications, using RFC 3856.

I have a situation in which end-to-end presence management wouldn't be suitable.

Still I'm wondering if server based presence management is a good idea. My thought is that it present a scalability issue. The point is that having the presence server would have to handle every single SUBSCRIBE & PUBLISH request then sends NOTIFY to every watchers.

Is it an efficient way to handle presence in a network with hundreds online users, everyone having tens of contact on their list.

Thank you for your comments

Luba Vincent