Final answer:
The southbound API that matches the description is OpenFlow. The correct option is c. OpenFlow
Step-by-step explanation:
The southbound API that matches the given description is OpenFlow. OpenFlow is an open standard protocol that allows communication between the control plane and the forwarding plane of a Software-Defined Networking (SDN) architecture. It follows an imperative model, where the controller directly manipulates the network devices using OpenFlow messages.
The southbound API that matches the description of using an imperative SDN model is OpenFlow. In an SDN architecture, southbound APIs are used to communicate between the SDN controller and the network devices.
OpenFlow is indeed an imperative approach, as it allows the SDN controller to proactively push rules to network devices, which then go on to process and forward traffic based on these rules. This is different from declarative approaches which would state the desired network behavior without explicitly detailing the actions to achieve it.
The correct option is c. OpenFlow