CU/DU/RU Split

In telecommunications, the CU/DU/RU split refers to the disaggregation of the gNB into a Central Unit (CU) hosting higher-layer protocols, a Distributed Unit (DU) hosting lower-layer real-time processing, and a Radio Unit (RU) handling RF. The split is connected by the F1 interface (CU-DU) and the fronthaul interface (DU-RU), and it underpins virtualized and Open RAN deployments.

Categories: Radio Access NetworkProtocols and StandardsCloud and Virtualization

CU/DU/RU Split 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.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how the specs interlock (for example 3GPP TS 33.501 with GSMA FS.34 for 5G SBA security), is essential for both design and audit work.

To place CU/DU/RU Split in the wider telecom-security picture, review O-RAN Alliance, Cloud RAN, RRH, ETSI ISG MEC, RIC and Open Fronthaul.

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