Which southbound API uses an imperative SDN model?

Which southbound API uses an imperative SDN model?

• A. NETCONF
• B. OnePK
• C. OpenFlow
• D. OpFlex

Answer: (C)

OpenFlow embodies an imperative SDN model: the controller directly programs the data plane by sending explicit commands to switches to install, modify, or delete specific flow entries. Each instruction specifies exactly what to match and what action to take, so the controller steps through concrete steps to shape packet handling. NetConf is a general configuration protocol for devices and doesn’t define per-flow data-plane actions in the same imperative sense. OpFlex uses a declarative, policy-driven approach where devices enforce policies rather than being told every exact flow to install. OnePK provides programmable access to devices but isn’t the canonical imperative data-plane programming interface used in SDN. So the best answer is OpenFlow.

OpenFlow embodies an imperative SDN model: the controller directly programs the data plane by sending explicit commands to switches to install, modify, or delete specific flow entries. Each instruction specifies exactly what to match and what action to take, so the controller steps through concrete steps to shape packet handling.

NetConf is a general configuration protocol for devices and doesn’t define per-flow data-plane actions in the same imperative sense. OpFlex uses a declarative, policy-driven approach where devices enforce policies rather than being told every exact flow to install. OnePK provides programmable access to devices but isn’t the canonical imperative data-plane programming interface used in SDN.

So the best answer is OpenFlow.