PFCP protocol refers to "Packet Forwarding Control Protocol". This protocol works between the control plane (e.g. the SMF) and the user plane (e.g. the UPF) in the 5G core network. It enables the control plane to instruct the user plane functions on how to handle user data traffic.

Below are the main roles of the PFCP protocol,

• Establish, modify, and release user plane sessions between 5G user plane network nodes.

• Enables the control plane to instruct the user plane functions to enforce quality of service (QoS) policies for user data traffic, (e.g. data rate, latency, and priority).

• Allows the control plane to configure the user plane functions to apply appropriate forwarding rules and policies to user data packets, (e.g. traffic detection, traffic steering, traffic filtering,..etc).

• Allows the user plane functions to report session-related information and measurement data to the control plane. This data can be used for charging and monitoring purposes.