O-DU (O-RAN Distributed Unit)

Also known as: O-RAN Distributed Unit

The O-DU is the O-RAN Alliance's disaggregated 5G gNB Distributed Unit that hosts the RLC, MAC and upper-PHY layers, terminating F1 toward the O-CU and Open Fronthaul (7-2x split) toward the O-RU. It handles time-critical scheduling and is a high-throughput target: fronthaul interception, PTP time-sync attacks and workload compromise on the O-Cloud host all sit inside the O-DU threat model.

Categories: Radio Access NetworkInternet and Routing

O-DU in context

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

Telecom networks depend on Internet-style routing (BGP, DNS, MPLS) for interconnect. Route hijacks and DNS abuse can degrade or intercept signaling, which is why RPKI and DNSSEC are now standard hardening for carrier networks.

To place O-DU in the wider telecom-security picture, review O-CU, O-RU, Open Fronthaul, Satellite Backhaul, OFDMA and RAN: each entry cross-references back to this page so you can walk the topic in either direction.

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