SDNController
An SDN controller is the software component in software-defined networking that provides the centralized control plane for the network. It communicates with forwarding devices (switches, routers) through southbound interfaces, translates network policies into forwarding rules, and exposes northbound APIs for applications and services to request network behavior. In typical deployments, the controller maintains a global view of the network topology, state, and policies, and uses it to optimize routing, perform traffic engineering, and enforce security.
Controllers can be centralized or distributed. In centralized deployments, a single controller instance makes decisions for
Common southbound protocols and interfaces include OpenFlow, NETCONF, and RESTCONF, while northbound APIs typically include RESTful