What is Software-Defined Networking (SDN)?

What is Software-Defined Networking (SDN)?

• A. A hardware-only networking approach that eliminates software.
• B. A method for encrypting data in transit across software networks.
• C. A model that decouples the control plane from the data plane, centralizing network management and programmability.
• D. A protocol used by routers to learn paths.

Answer: (C)

SDN centers on separating the decisions about where traffic should go from the devices that actually forward the traffic. The control plane, which makes routing decisions and policies, is centralized in a software controller, while the data plane (the forwarding devices) simply moves packets based on the controller’s instructions. This setup lets you program the network from software, apply changes quickly across the whole network, and automate tasks without configuring each switch individually. The central controller can implement policy, optimize paths, and adapt to new needs in real time, all through software interfaces. This is why the best description emphasizes decoupling the control plane from the data plane and centralizing management and programmability. The other ideas describe things like a hardware-only approach, encrypting data, or a routing protocol, which don’t capture the core SDN model.

SDN centers on separating the decisions about where traffic should go from the devices that actually forward the traffic. The control plane, which makes routing decisions and policies, is centralized in a software controller, while the data plane (the forwarding devices) simply moves packets based on the controller’s instructions. This setup lets you program the network from software, apply changes quickly across the whole network, and automate tasks without configuring each switch individually. The central controller can implement policy, optimize paths, and adapt to new needs in real time, all through software interfaces.

This is why the best description emphasizes decoupling the control plane from the data plane and centralizing management and programmability. The other ideas describe things like a hardware-only approach, encrypting data, or a routing protocol, which don’t capture the core SDN model.