5G Session management is an element of the 5G SBA (Service based Architecture). It is mainly responsible for interacting with decoupled data plane. It performs functions to create, update and remove PDU (Protocol data unit) and also manages various session contexts with the UPF (User Plane Function). 5GC session management was defined which provides solutions for efficient user plane connectivity. The most important tool for achieving an efficient user plane path is the UPF selection which takes place at the PDU session establishment.
The session management functionality of the 5G system has the responsibility for the setup of the connectivity for the UE towards data networks as well as managing the user plane for the connectivity. The session management function is the control function which manages all the user sessions and it includes session establishment, session modification and release of sessions. Allocation of IP addresses for various PDU sessions is also performed by the Session management function. SMF communicates with the UE in an indirect mode through the AMF for all session related messages and information.