application function (LTE, NGN) (AF)
InLTE networks, the Application Function(AF) corresponds to the Call Session Control Function( CSCF) in IPMultimedia Subsystems( IMS).
The Application Function interacts with services and applications requested by the PCC architecture, Policy Control and Charging (PCC). The Application Function extracts session information from signaling to support the Policy and Charging Rules Function( PCRF). Supported functions include the subscriber identifier, the IP address of the subscriber device, the media type and its format, the bandwidth, the description of the data stream with source address and destination address as well as the protocol used, various indicators and AF identifiers.