In software-defined networking, what function is performed by an SDN controller?

In software-defined networking (SDN), the role of the SDN controller is primarily related to the control plane. The controller acts as the brain of the network, managing and directing the behavior of the underlying data plane elements, such as switches and routers.

The control plane is responsible for maintaining the network topology, managing network policies, and facilitating communication between different network devices. Through a centralized SDN controller, network administrators can configure and manage the network dynamically, leading to more efficient use of resources and enhanced flexibility in handling various networking tasks.

This separation of the control plane from the data plane (which is responsible for handling the actual data packets being transmitted through the network) allows for centralized control and management of the network infrastructure, which is a key aspect of SDN architecture. As such, understanding the distinction between these planes is crucial for grasping how SDN operates and the advantages it offers in terms of network management and optimization.