Software Defined Networking (SDN) is an intelligent approach to networking in which network control is software-based and decoupled from hardware. Two planes are available in the network components for decoupling: the Control Plane( CP) and the Data Plane( DP). The decisions for transporting the data packets are made on the Control Plane, which is independent of the underlying Data Plane, which is responsible for forwarding the data packets to the receiving location.
In conventional networks, the data packets are forwarded by the switches according to the specifications of the proprietary firmware. The data packets reach the receiving location via the same connection paths. In intelligent switches, the different data packets are analyzed and reach their destination via different connections.
The situation is different in Software Defined Networking (SDN) where the administrator can optimize the connection paths by traffic shaping. If necessary, the administrator can change the switches' defaults in terms of prioritization or by filtering out certain data packets. This technology is particularly suitable for cloud computing with many different clouds, as the administrator can manage the traffic load flexibly and efficiently using traffic shaping. In addition, less expensive switches can be used. By separating the Control Plane from the Data Plane, various applications such as network virtualization can be implemented much more easily.
One of the best-known specifications for Software Defined Networking is the open standard OpenFlow from the Open Networking Foundation( ONF), which administrators can use to control routing tables. Other infrastructure protocols include Virtual Extensible LANs(VXLAN) and Network Virtualization using Generic Routing Encapsulation( NVGRE).