This annex specifies the enhancement to 3GPP charging architecture and framework in which, when required for a specific service, the Charging Trigger Function is split between the UE that supports that service and the network element or service element. As described in clause 18.104.22.168
, the CTF consists of the Accounting Metrics Collection (AMC) function block and the Accounting Data Forwarding (ADF) function block. For select services, the CTF (AMC) is located in the UE and the CTF (ADF) is located in the network element or service element reachable by an application layer protocol. The applicability of this distributed CTF architecture is described in each specific middle tier charging TS that utilizes this construct.
In the present document the distributed CTF is only available for offline charging.
For the purposes of this annex, the following symbols apply:
Offline charging reference point between a UE and the service NE for charging purposes
For the purposes of this annex, the following abbreviations apply:
Charging Trigger Function (Accounting Metrics Collection)
Charging Trigger Function (Accounting Data Forwarding)