Software-defined networking (SDN) is becoming a huge deal. To many people, the term is opaque, almost to the point of being meaningless. After all, what part of anyone's network isn't software-dependent? Every firewall, router, and switch you run has software (firmware) to control it. But with SDN, the management and control planes aren't the only ones implemented in software -- the bulk of the data plane is as well.
Among the variety of important ramifications, one in particular stands out: With SDN, you're using commodity server hardware (typically on top of or within a virtualization hypervisor) to manage, control, and move your network's data. This is different from the pre-SDN approach of running management and control software on top of purpose-specific ASICs (specialty chips) that move the bits to and fro. This means you can deploy entire new network components, configure them, and bring them into production without touching a screwdriver or a piece of sheetmetal, thanks to SDN.
Early days for SDN