A controller communicates with the data plane using which type of interface, including examples like NETCONF, OpenFlow, OpFlex, or OnePK?

A controller communicates with the data plane using which type of interface, including examples like NETCONF, OpenFlow, OpFlex, or OnePK?

• A. Northbound API
• B. Eastbound API
• C. Southbound API
• D. Westbound API

Answer: (C)

In SDN, the control plane communicates with the devices that actually forward traffic through a southbound API. This interface lets the controller configure switches and routers, install forwarding rules, and gather telemetry from the data plane. Protocols like OpenFlow, NETCONF, OpFlex, and OnePK are examples of these southbound protocols because they directly manage the network devices. The northbound interface, by contrast, is used by applications talking to the controller to request services or express intents, while east/west interfaces handle communication between controllers in a distributed setup. So the interface that links the controller to the data plane is the southbound API.

In SDN, the control plane communicates with the devices that actually forward traffic through a southbound API. This interface lets the controller configure switches and routers, install forwarding rules, and gather telemetry from the data plane. Protocols like OpenFlow, NETCONF, OpFlex, and OnePK are examples of these southbound protocols because they directly manage the network devices. The northbound interface, by contrast, is used by applications talking to the controller to request services or express intents, while east/west interfaces handle communication between controllers in a distributed setup. So the interface that links the controller to the data plane is the southbound API.