Section: 5.2.5.6 Npcf_UEPolicyControl Service 5.2.5.6.1 General
Content: Service description: NF Service Consumer, e.g. AMF, or the PCF serving the PDU Session when a UE attaches in EPS, may create and manage a UE Policy Association in the PCF through which the NF Service Consumer receives Policy Control Request Trigger of UE Policy Association. The association allows (V-)PCF to provide UE policy information to the UE transparently through the NF Service Consumer using NAS TRANSPORT message to carry: - UE policy information as defined in clause 6.6 of TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [20]. In the case of roaming, the URSP rules are provided by H-PCF and the ANDSP rules may be provided by V-PCF or H-PCF or both. As part of this service, the PCF may provide the NF Service Consumer, e.g. AMF, with policy information about the UE that may contain: - Policy Control Request Trigger of UE Policy Association. When such a Policy Control Request Trigger condition is met, the NF Service Consumer, e.g. AMF, shall contact PCF and provide information on the Policy Request Trigger condition that has been met. In the case of roaming, the V-PCF may subscribe to AMF or the H-PCF may subscribe to AMF via V-PCF. At Npcf_UEPolicyControl_Create, the NF Service Consumer, e.g. AMF, requests the creation of a corresponding "UE Policy Association" with the PCF (Npcf_UEPolicyControl_Create) and provides relevant parameters about the UE context to the PCF. When the PCF has created the UE Policy Association, the PCF may provide policy information as defined above. When a Policy Control Request Trigger condition is met, the NF Service Consumer, e.g. AMF, requests the update (Npcf_UEPolicyControl_Update) of the UE Policy Association by providing information on the condition(s) that have been met. The PCF may provide updated policy information to the NF Service Consumer. During the AMF relocation, if the target AMF receives the PCF ID from source AMF and the target AMF decides to contact with the PCF identified by the PCF ID based on the local policies, the target AMF requests the update (Npcf_UEPolicyControl_Update) of the UE Policy Association. If a Policy Control Request Trigger condition is met, the information matching the trigger condition may also be provided by the target AMF. The PCF may provide updated policy information to the target AMF. The PCF may at any time provide updated policy information (Npcf_UEPolicyControl_UpdateNotify). At UE deregistration the NF Service Consumer, e.g. AMF, or the PCF serving the PDU Session when a UE detaches from EPS, requests the deletion of the corresponding UE Policy Association.