Rx Interface and Rx/Gx signalling flows
The present document provides the stage 3 specification of the Rx reference point interface.
The functional requirements and the stage 2 specifications of the Rx reference point are contained in 3GPP TS 23.125 [2]. The Rx reference point is used to exchange Flow Based Charging information between the Charging Rules Function (CRF) and the Application Function (AF).
Whenever it is possible the present document specifies the protocol by reference to specifications produced by the IETF within the scope of Diameter and to the Gq specification 3GPP TS 29.209 [4].
The present specification also provides detailed signalling flows for FBC procedures over the interfaces that correspond to Rx and Gx reference points.