Software Defined Networking
SDN uses canned processes to provision the network. For example, instead of building a network tap using an appliance, users should be able to program the network when they want to build a tap.
SDN makes the network programmable by separating the control plane (telling the network what goes where) from the data plane (sending packets to specific destinations). It relies on switches that can be programmed through an SDN controller using an industry standard control protocol, such as OpenFlow.
SDN changes the physical network, and therefore is really a new externally driven means to provision and manage the network. A use case may involve moving a large “elephant flow” from a 1G port to a 10G port, or aggregation of lot of “mice flows” to one 1G port. SDN is implemented on network switches, rather than x86 servers. BigSwitch and Pica8 are examples of companies selling SDN-related products.
SDN requires a new network construct where the data and control planes are separate.