Cisco, Brocade, Dell among others have jumped on board and look to ride the wave that is software defined networking. This despite experts' assertions that SDNs threaten Cisco's dominance in the tech industry.
As is somewhat typical of emerging technologies, there isn't a universally agreed to definition of what is meant by software defined networking (SDN). Over the last year or two most of the definitions have focused on the decoupling of the network control plane from the network forwarding plane.
The definition of SDN that is currently emerging focuses somewhat less on decoupling and more on providing programmatic interfaces into network equipment, whether or not there is a separation of the control and forwarding planes. A minor reason for this shift in focus is because Cisco recently announced that as part of its SDN offerings, it will provide APIs into multiple platforms that they provide.