Advice of charge for internet protocol multimedia subsystem services without utilizing an application server

摘要

Advice of charge information is provided utilizing the session initiation protocol (SIP) in an Internet protocol multimedia subsystem without utilizing an application server. The advice of charge message is provided to a user via the serving call/session control function and the home subscription server. When a request for a service is received by the serving call/session control function, the state of a binary, Boolean flag associated with the originator of the request is analyzed. Depending upon the state of the flag, either the request is routed to its intended destination, or an advice of charge message is routed to originating user, advising the user of the charge for the requested service. If the user accepts the charge, the serving call/session control function transmits the request for routing to the intended destination, and the flag is toggled. If the user declines the charge, the call is ended.