I can think of
two application which might be appealing.
The first one is a pbx which can be deployed in a company. All internal
calls are routed through it. One can distribute the central ser server
functions into multiple smaller ser servers.
I guess for PBX applications asterisk is better.
In my experience, * is not
something I'd recommend to just anyone. Unless
one is willing to spend significant amount of time to enhance the code...
Richard