Open Fronthaul (O-RAN 7-2x Fronthaul Interface)

Also known as: OFH, 7-2x Fronthaul

The Open Fronthaul is the O-RAN Alliance's standardised interface between O-DU and O-RU at the 7-2x functional split. It defines four planes: CUS-Plane (control, user, synchronisation) over eCPRI, M-Plane for management over NETCONF/YANG, and S-Plane for time sync via PTP/SyncE. Because Open Fronthaul is a multi-vendor and often physically exposed link, WG4 mandates 802.1X, MACsec/IPsec and PTP authentication to prevent interception and time-sync attacks.

Categories: Radio Access NetworkProtocols and Standards

Open Fronthaul 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 Open Fronthaul in the wider telecom-security picture, review E2SM, SSH, O-RAN Alliance, CU/DU/RU Split, O-DU and O-RU.

Related terms

Equipment

O-RAN units and RIC (O-RU, O-DU, O-CU, RIC, SMO)

Articles in the P1 mobile network security guide

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