A1 Interface (Non-RT RIC to Near-RT RIC Interface)
Also known as: A1, A1-P, A1-EI, A1-ML
The A1 interface is the O-RAN control-plane interface from the Non-RT RIC (in the SMO) down to the Near-RT RIC. It carries three service categories: A1-P (policy) to guide xApp behaviour, A1-EI (enrichment information) to feed contextual data to xApps, and A1-ML (ML model management) for model lifecycle. Compromise of A1 lets an attacker push arbitrary policies and models into the live RAN.
Categories: Radio Access Network
A1 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.
To place A1 Interface in the wider telecom-security picture, review AMF, O-RAN Interfaces (A1, E2, O1, O2), Non-RT RIC, E2 Interface, E2AP and O1 Interface.
Related terms
Equipment
O-RAN units and RIC (O-RU, O-DU, O-CU, RIC, SMO)
Related topic hubs
- Open RAN Security O-RAN xApp/rApp, E2/A1/O1 interfaces and RIC security.
- Diameter Security 4G/LTE Diameter threats across IPX/roaming and DEA defenses.
- 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.