Policy and charging control over Rx reference point
The present document provides the stage 3 specification of the Rx reference point for the present release. The functional requirements and the stage 2 specifications of the Rx reference point are contained in 3GPP TS 23.203 [2].
The Rx reference point lies between the Application Function (AF) and the Policy and Charging Rule Function (PCRF). In the 5GS the Rx reference point resides between the AF and the Policy Control Function (PCF) as specified in 3GPP TS 23.501 [55] and 3GPP TS 23.503 [56].
NOTE: Interactions between the PCF and the AF using the 5GS Npcf_PolicyAuthorization service (the N5 reference point) are defined in 3GPP TS 29.514 [57].
The Rx interface which is based on RESTful HTTP and XML is specified in 3GPP TS 29.201 [37].
Whenever it is possible the present document specifies the requirements for the protocol by reference to specifications produced by the IETF within the scope of Diameter. Where this is not possible, extensions to Diameter are defined within the present document.