Fronthaul

Fronthaul is the network segment between the Remote Radio Head (or O-RAN Radio Unit) and the centralised baseband processing in Cloud RAN and vRAN architectures. It typically uses CPRI or the packet-based eCPRI over fibre, with strict latency and synchronisation requirements. Some functional splits expose unciphered user data, so fronthaul must be physically protected or encrypted with MACsec or IPsec.

Categories: Radio Access NetworkSecurity ControlsCloud and Virtualization

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.

Security controls in telecom span signaling firewalls (SS7/Diameter/GTP screening at the network edge), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both the packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36 and, in Europe, NIS2 sectoral rules.

To place Fronthaul in the wider telecom-security picture, review RRH, Cloud RAN, IGW, Satellite Backhaul, MACsec and CU/DU/RU Split.

Related terms

Equipment

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

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