O-RAN Interfaces (A1, E2, O1, O2)

O-RAN Interfaces (A1, E2, O1, O2) 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.

Signaling protocols carry the control-plane messages that set up calls, register subscribers 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 as top-tier telecom risk.

To place O-RAN Interfaces (A1, E2, O1, O2) in the wider telecom-security picture, review Revenue Assurance, O1 Interface, Diameter, Interconnect Security Model, Man-in-the-Middle (MITM) and SC: each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

• Revenue Assurance
• O1 Interface
• Diameter
• Interconnect Security Model
• Man-in-the-Middle (MITM)
• SC
• 5G Reference Points
• F1 Interface

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.
• Diameter Attacks S6a IDR/PUR/CLR abuse, subscriber tracking, LTE signaling attacks.
• Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.

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.