SDN : Software-Defined Networking. It is a new network architecture that comprised different network technologies to build a flexible, scalabile, agile and easy manageble networks. SDN does this job by separating conrtol and forwarding planes.
Forwarding Plane : The bottom layer of SDN that is full of physical or virtual forwarding devices. Data Plane.
Control Plane : The middle layer of SDN that includes Network Operating System and SDN Controller.
Application Plane: The top layer of SDN that includes Applications.
Southbound Interface : The interface between the controller and the data plane forwarding devices.
Northbound Interface : The interface between the controller and the application plane.
API : Application Programmable Interface. Provide systems and sowftware interaction.
Forwarding Switch : SDN Forwarding Switch that is used in data plane
Controller : The central control mechanims of SDN network that controls forwarding plane.
NFV : Network Functions Virtualization. Virtualisation of the different skilled physical network devices with their virtual counterparts.
Flow : Sequence of packet between the source and the destination.
Flow Rules : Actions set for the flow
Flow Table : Tables on the switch that handles the traffic flow
Open Flow : Southbound Interface API, that provide the communication of SDN Controller and SDN Data Plane devices.