[asterisk-users] SIP carrier billing technicalities

[Robert McNaught]

Hi,

Does anyone know anything about the following?

In a hosted environment where several area DIDs are provisioned on a
single server, how do most carriers establish the origination DID,
number.

Asterisk allows us to modify the CallerID, name, number and DNID
channel variables before dialling out via SIP.  Most carriers will
allow us to spoof a callerID when placing a call, and pass it forward.
 We can also spoof the DNID also before the call is placed, although I
am not sure this is carried forward to the outgoing proxy, using SIP.

Do most carriers the carrier just use CallerID as an origination
number?  As far as I am aware, the concept of a BTN is gone with
SIP....

Does this mean its possible to save money on your bill, by modifying
CallerID so that the origination number is seen to be a local call?

anyone care to comment?

Robert