E.1 General

29.2143GPPPolicy and charging control over Rx reference pointRelease 17TS

In the 5GS the Rx reference point is defined between the the PCF and the AF. The relationship between the involved functional entities is depicted in figure E.1.1. The overall PCC architecture is depicted in clause 4 of 3GPP TS 29.513 [59].

Figure E.1.1: Rx reference model in 5GS

5GS supports an interworking with AFs via the Rx interface. Interworking with AFs related to existing IMS services is described in 3GPP TS 23.228 [16]. Interworking with AFs related to existing Mission Critical services is described in TS 23.280 [60]. The PCF in 5GS supports the corresponding Rx procedures and requirements defined in 3GPP TS 23.203 [2]. The stage 2 requirements for 5GS supporting Rx interface are described in 3GPP TS 23.503 [56].

The PCF exchanges PCC rules with the SMF over the N7 interface as specified in 3GPP TS 29.512 [57].

Signalling flows related to the both Rx and N7 interfaces are specified in 3GPP TS 29.513 [59].

The generic mechanisms for interaction between the AF and the PCF are described in main clauses in this specification and with the following clarifications:

– description of the PCRF and the PCEF applies to the PCF and the SMF respectively;

– description of the SPR applies to the UDR;

– BBERF is not applicable in 5GS;

– an IP-CAN bearer in this specification shall be interpreted as a 5GS QoS flow;

– an IP-CAN session in this specification shall be interpreted as a 5GS PDU session of type IP;

– APN is equivalent to DNN;

– the following values of the Specific-Action AVP defined in clause 5.3.13 are applicable only to a PCF: EPS_FALLBACK (17) and INDICATION_OF_REALLOCATION_OF_CREDIT (18);

– when the serving network is an SNPN and the serving network information is provided to the AF, the NID may optionally be part of the serving network identifier, as specified in clause E.5; and

– the 5G-RAN-NAS-Release-Cause AVP defined in clause 5.3.69 is applicable only to a PCF. When the RAN-NAS-Cause feature is supported, it encodes the 5GS RAN cause and/or NAS cause, when available.

The specific mechanisms for the interaction between the AF and the PCF are described in the subclauses below.