How it Works

The SMF integrates the CHF and PCF functions based on the following information:

  • Policy control request triggers—received in the SM policy decision during

    • PDU session establishment or

    • PCF or UE initial modification

  • Session-level or rating-group-level charging triggers—received during

    • PDU session establishment or

    • in response to

      • SMF-initiated Charging Update Request

      • CHF-initiated Charging Update Notify Request

The SMF supports the following access-side information to detect the PCF and CHF triggers. The SMF sends the trigger information to the CHF and PCF during the N2-based handover.

Access-Side Information for PCF and CHF Triggers

Access-Side

CHF-Triggers

PCF-Triggers

UserLocation

USER_LOCATION_CHANGE

SAREA_CH

UeTimeZone

UE_TIMEZONE_CHANGE

SAREA_CH

ServingNetwork

PLMN_CHANGE

PLMN_CH

TargetServingNfId

SERVING_NODE_CHANGE