5G basics
Session Management Function (SMF)
Description
The SMF, or Session Management Function, is responsible for managing the sessions, e.g., IP data connections of end-user devices in the 5G network. This includes tasks such as establishing, modifying, and releasing individual sessions and allocating IP addresses for each session.
The SMF communicates indirectly with end-user devices through the AMF, which forwards session-related messages between the devices and the SMF via the NAS protocol.
In addition, the SMF interacts with other network functions through its service-based interface and controls the different UPF (User Plane Function) network functions in the network through the N4 network interface. This control includes configuring traffic steering and traffic enforcement for individual sessions in the UPF.
Security importance
In its role, the SMF manages the user-plane (UP) security policy of the session. The UP security policy typically includes measures to protect user data via integrity over the radio network.