Software Defined Networking (SDN)
Generally speaking, SDN is the ability to utilize an application framework (software) function to control the movement of network traffic through the entire network. More specifically, the idea is to separate the control plane (decision making, “brains”) of a network device, from the data plane (data movement, “braun”), and then to centralize the control plane of multiple devices under a single control point. This single control point can then be a part of a higher-level management or orchestration framework, which allows for a more holistic view of the entire infrastructure.
Other terms that may be used in congestion with SDN; abstraction, OpenFlow, OpenDaylight, Controller. Application Programming Interface