Also known as: southbound interface, SBI
Quick Definition
APIs on an SDN controller that communicate with and programme the network devices below.
Southbound APIs are used by the SDN controller to push configuration and forwarding rules down to network devices. Examples include OpenFlow (programmes flow tables), NETCONF (using YANG data models over SSH), RESTCONF (HTTP-based NETCONF alternative), and gRPC. The controller uses southbound APIs to tell each device what traffic to forward and how.
Southbound = toward devices (below the controller). NETCONF uses SSH (TCP port 830) and YANG data models. RESTCONF is the HTTP-based alternative to NETCONF. Both are examples of southbound interfaces.
An architecture that separates the network control plane from the data plane, enabling centralised programmability.
APIs on an SDN controller that allow applications and management tools to communicate with the controller.
Cisco's SDN controller and network management platform providing centralised automation and analytics.
Southbound APIs are used by the SDN controller to push configuration and forwarding rules down to network devices. Examples include OpenFlow (programmes flow tables), NETCONF (using YANG data models over SSH), RESTCONF (HTTP-based NETCONF alternative), and gRPC. The controller uses southbound APIs to tell each device what traffic to forward and how.
Southbound = toward devices (below the controller). NETCONF uses SSH (TCP port 830) and YANG data models. RESTCONF is the HTTP-based alternative to NETCONF. Both are examples of southbound interfaces.
Southbound API falls under the Automation domain of the 200-301 exam. Understanding it in context with related terms like northbound-api and sdn is essential for answering scenario-based questions correctly.