RAN (Radio Access Network)

The Radio Access Network is the part of a mobile network that connects user devices to the core via radio. In 2G/3G it comprises the BTS/Node B and BSC/RNC; in 4G the eNodeB; and in 5G the gNB, often split into Centralised Unit and Distributed Unit. The RAN handles air-interface scheduling, ciphering, integrity protection, and handovers. Its security exposure spans rogue base stations, fronthaul interception, and supply-chain risk in the radio equipment itself, all of which are amplified by Open RAN multi-vendor architectures.

Categories: Radio Access NetworkCore NetworkThreats and Attacks

RAN 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 RAN in the wider telecom-security picture, review BTS, Open RAN, Jamming, RF, Slice Hopping and RNC.

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