US Patent 9819540 Software defined network controller

An extensible software defined network (SDN) controller is described that provides an application-aware framework that enable a variety of different user applications to communicate with the controller and that allows the controller to automatically configure devices in a network based on the needs of the applications. For example, the controller includes a plurality of different northbound interfaces that enable a variety of different user applications to communicate with the controller. The controller also includes multiple southbound protocols for configuring and enabling functionality in network devices based on the communications with the user applications.