Software-defined networking (SDN) removes the limitations of hardware by, for example, allowing the networking hardware's behavior to be changed on the fly. The shift to SDN has the potential to turn the hardware-driven concept of networking into one that's more software-defined and on-demand. This column reviews the advantages of SDN, explains related business and technology opportunities, and looks at the potential for SDN solutions to live in the cloud, providing an on-demand networking capability that could offer better and cheaper approaches to networking, and the ability to place network volatility into its own domain.