What is UPF?
The UPF is the 5G Core network function responsible for all user plane data processing and forwarding. It is the gateway between the 5G RAN and external data networks (internet, enterprise intranets) and is the sole 5GC function that handles actual user traffic. The UPF replaces and consolidates the 4G EPC’s S-GW and P-GW user plane components.
How Does UPF Work?
Controlled by the SMF via the N4 interface (PFCP protocol), the UPF receives forwarding rules, QoS enforcement policies, and traffic measurement instructions. It performs: GTP-U tunnel termination (N3 from gNB), packet routing and forwarding, QoS marking and policing, traffic usage reporting, and Uplink Classifier (ULCL) for MEC traffic steering. UPFs can be chained: an I-UPF (Intermediate) at the edge, and a PSA-UPF (PDU Session Anchor) at the centre.
Use Cases
All 5G data forwarding, edge computing (MEC) local traffic breakout, network slice user plane differentiation, lawful intercept traffic copy, traffic analytics and charging.
3GPP / Standards Reference
3GPP TS 29.244 (N4 Interface — PFCP Protocol), TS 23.501
Related Terms
SMF | AMF | CUPS | MEC | Network Slicing | EPC
Learn More
This glossary entry is part of the 5GWorldPro Complete 5G Glossary. To go deeper into 5G architecture and technology, explore our 5G Training courses.
