Patent ID: 7599478

Claim:
An IP Multimedia Subsystem (IMS) gateway system for providing online charging in an IMS network, the IMS gateway system comprising: a first interface operable to communicate with a call session control function (CSCF) according to a first protocol; a second interface operable to communicate with an online charging server (OCS) according to a second protocol; and a charging trigger system coupled to the first interface and the second interface, the charging trigger system: receives a first message for a call session through the first interface from the CSCF wherein the first message is in the first protocol, processes the first message to determine whether to contact the OCS for online charging for the call session, generates a second message that comprises a charging request to transmit to the OCS responsive to a determination to contact the OCS, maps fields of the first message in the first protocol to fields in the second message in the second protocol, transmits the second message to the OCS through the second interface for online charging for the call session, receives a third message from the OCS responding to the second message, generates a fourth message indicating whether charging was allowed or denied; and transmits the fourth message to the CSCF through the first interface.