Xn Interface

In telecommunications, Xn is the 3GPP-defined interface between two gNBs (or between a gNB and an ng-eNB) used for handover signaling, dual connectivity, and load management. Xn-C carries control plane and Xn-U carries user plane, both protected with IPsec.

Categories: Radio Access NetworkSignalingSecurity Controls

Xn Interface 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.

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA FS.11 / FS.19 / FS.20 as a top-tier telecom risk.

To place Xn Interface in the wider telecom-security picture, review F1 Interface, Control Plane Security, Lawful Interception, N32 Interface (5G), RTP and SIP.

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