Actually Charging is based on different Charging Scenarios.
Basic Principles of OCS:
For online charging the basic structure follows a mechanism
where the online client (CTF) requests resource allocation and reports credit
control information to the OCS (Online Charging System).
The online client implements the state machine described
in RFC 4006 for
"CLIENT, EVENT BASED" and/or "CLIENT, SESSION BASED".
a. For Immediate Event Charging (IEC), client uses
the "CLIENT, EVENT BASED" state machine
b. For Event Charging with Unit Reservation (ECUR)
it uses the "CLIENT, SESSION BASED" state machine for the first and
final interrogations.
Three
cases for control of users credit for online charging are:
- Immediate Event Charging (IEC)
- Event Charging with Unit Reservation (ECUR)
- Session Charging with Unit Reservation (SCUR)
In the case of IEC, the credit control
process for events is controlled by the corresponding CC-Requested-Type EVENT_REQUEST that
is sent with Credit-Control-Request (CCR) for a given credit
control event.
In the case of ECUR
the CC-Request-Type INITIAL / TERMINATION_REQUEST are used for
charging for a given credit control event, however, where a reservation
is made prior to service delivery and committed on execution of a successful
delivery.
In SCUR, the CC-Request-Type INITIAL
/ UPDATE and TERMINATION_REQUEST.
