I’m looking into the first design phase of a setup like this:

PSTN <-> FS <-> Various SIP PBXs or nothing <-> SBC <-> Internet <-> Customer

Where I’m considering using the FS as the SBC and as an alternative to OpenSIPS (OpenSER), where the FS has the advantage of a design having only one type of switch, e.g. less education to the team supporting the system.

If this should work, the FS should be able to route SIP messages such as NOTIFY, SUBSCRIBE etc. Is that possible, and what are the measures to implement such a routing function? /Jon