O1 Interface (O-RAN Management Interface)

Also known as: O1

The O1 interface is the O-RAN management-plane interface from the SMO to O-RAN managed functions (O-CU, O-DU, O-RU, Near-RT RIC). It carries FCAPS operations (fault, configuration, accounting, performance, security) using NETCONF/YANG and file-transfer protocols. O1 is a high-value target: compromise gives an attacker configuration control over the entire RAN.

Categories: Radio Access NetworkSignalingOperations and Business

O1 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 O1 Interface in the wider telecom-security picture, review O-RAN Interfaces (A1, E2, O1, O2), AMF, Xn Interface, BSS, Man-in-the-Middle (MITM) and Operating System (OS).

Related terms

Equipment

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

Articles in the P1 mobile network security guide

Related topic hubs

  • Open RAN Security O-RAN xApp/rApp, E2/A1/O1 interfaces and RIC security.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • NAS Security Non-Access Stratum security, integrity and ciphering algorithms.

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.