El Miércoles, 12 de Agosto de 2009, Olle E. Johansson escribió:
Anyway, there's some work in the IETF to handle the register for multiple DID's, since the way it's used now clearly violates what's in the RFCs and there is an obvious need to register for "SIP trunks".
I implemented this in an "ellegant" way:
- The SIP trunk (Asterisk?) registers with Contact "s@IP" (or any contact). - It has associated 3 PSTN numbers in the proxy/registrar. - When the proxy receives a call for one of these 3 numbers it changes the RURI according to the location of the client (lookup("location")) and adds a header whose value is the dialed PSTN number in E164 format: P-Dialed-Number: +34987654321
So: - "To" remains unchanged. - RURI arriving to the client matches its registration's Contact. - The client must inspect a custom header to know the real destination number of the call.
However, I've read some RFC with a similar solution (I think it uses "P- Called-Party" header, but later the complex "History" header appeared and...).