SAI Switch Abstraction Interface

Overview

SAI (Switch Abstraction Interface) is OCP's hardware abstraction layer enabling multi-vendor switch silicon programming through a standardized API. Originally developed to allow SONiC to run across different ASIC vendors, SAI has become the central technology enabling the open networking ecosystem, with adoption spanning SONiC, DENT OS, and FBOSS. SAI defines object types, attributes, and APIs for programming forwarding tables, ACLs, tunnels, telemetry, and monitoring functions, insulating the network operating system from vendor-specific SDK differences.

At the 2023 OCP Global Summit Networking track, SAI appeared in 15+ of 20 presentations, reflecting its role as the foundational abstraction for virtually every open networking innovation — from AI traffic engineering and telemetry to WAN routing, cable diagnostics, and security. The SAI specification is maintained through the OCP SAI sub-project (led by Rita Hui, Microsoft), with versions 1.12 and 1.13 released in 2023.