AMF: Access and Mobility Management

The AMF — Gateway to the Core

The Access and Mobility Management Function is the first core network function that every UE communicates with. It terminates the N1 interface carrying NAS signaling from the UE and the N2 interface carrying NG-AP messages from the gNB. The AMF handles the complete UE registration lifecycle including initial registration, periodic registration updates, and de-registration. It manages connection states by tracking whether a UE is in CM-IDLE or CM-CONNECTED mode and coordinates mobility events when a UE moves between gNBs, including inter-AMF handover scenarios.