Code of Federal Regulations Title 47. Telecommunication § 47.64.6301 Caller ID authentication

(1) Authenticate and verify caller identification information for all SIP calls that exclusively transit its own network;

(2) Authenticate caller identification information for all SIP calls it originates and that it will exchange with another voice service provider or intermediate provider and, to the extent technically feasible, transmit that call with authenticated caller identification information to the next voice service provider or intermediate provider in the call path;  and

(3) Verify caller identification information for all SIP calls it receives from another voice service provider or intermediate provider which it will terminate and for which the caller identification information has been authenticated.