PCF

Technical Explanation

The PCF evolves the 4G PCRF into the cloud-native 5G architecture. It determines policy and QoS rules for network slices and PDU sessions based on subscription information from UDR and operational state. PCF constructs URSP (UE Route Selection Policy) rules and sends them to the UE via AMF/NAS, directing the device on which traffic flows to bind to which network slices and DNNs. It also sets 5G QoS Flow parameters (5QI, ARP, MBR, GBR) applied by SMF and UPF.

Key Functions

• QoS policy decision and flow rule definition (5QI, ARP, GFBR, MFBR)
• Provisioning of UE Route Selection Policy (URSP) for Network Slicing
• Access and Mobility policy authorization for AMF
• Charging policy determination and interaction with CHF (Charging Function)