Software-defined networking is enjoying a lot of attention lately -- and a lot of that is generated by vendors who see an opportunity to chip away at the stranglehold Cisco Systems has held on the networking space for the last couple of decades.

There are plenty of people claiming to provide the only clear way to define SDN. Most of their definitions seem clear as mud to me. We hear SDN separates the network control plane from the data plane, prying the control logic of the network out of the switch or routers and placing it into centralized servers. This way, data-forwarding decisions can be made based on holistic views of the information distribution needed, rather than assessments of physical ports and pathways between connected devices.