a1ap

A1AP, short for A1 Application Protocol, is a communications protocol used within the O-RAN Alliance framework to support AI/ML-driven management of the radio access network. It operates on the A1 interface between the Non-Real-Time (Non-RT) RIC and the Near-Real-Time (Near-RT) RIC, enabling policy-based control and machine-learning model governance for RAN optimization.

A1AP provides the messaging used for policy orchestration and model governance, including the transfer of policies, policy decisions, and machine-learning model information and telemetry. The protocol is designed to be transport- and encoding-agnostic, with implementations typically running over a secure transport such as TLS/TCP and using encoding schemes chosen by the stack (for example ASN.1 or JSON).

Relation to other interfaces: A1AP is part of the broader A1 interface family in O-RAN and complements other interfaces such as E2 and C1 within the Near-RT and Non-RT RIC architecture. Its focus is AI/ML governance, policy enforcement, and model management, while other protocols handle additional control and data plane interactions among RAN components.

Implementation and usage: A1AP has been implemented in various open-source and vendor stacks as part of O-RAN deployments. It is used to convey intents for network optimization, updates to ML models, and telemetry that informs policy decisions and model selection.

See also: O-RAN Alliance, A1 interface, Near-RT RIC, Non-RT RIC, E2 interface.