AMF (Access and Mobility Management Function)

The Access and Mobility Management Function is the 5G control-plane network function that terminates the N1 NAS interface from the UE and the N2 interface from the gNB. It handles registration, connection management, mobility, and reachability, delegates authentication to the AUSF, and steers session requests to the appropriate SMF. The AMF is the 5G analogue of the 4G MME and is a high-value target because compromise enables tracking, denial of service, and forced bidding-down of security capabilities.

Categories: Radio Access NetworkCore NetworkSignaling

AMF in context

The radio access network is the layer where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations, downgrade attacks and jamming, and defenses hinge on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

The mobile core is where subscriber sessions, mobility and policy live. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

To place AMF in the wider telecom-security picture, review MME, gNodeB, CSCF, IAP, TCAP and NGAP.

Related terms

Equipment

Mobility management (MME, AMF, SGSN)

Articles in the P1 mobile network security guide

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