Software Defined Networking (SDN) has been a hot topic for years. As is typically the case with a new technology or architecture, the initial set of articles on SDN did their best to identify the impact that SDN would have, but often these articles were wrong. For example, a lot of the initial discussion of SDN focused on how SDN separates the control plane from the forwarding plane and how that separation would result in switches and routers becoming commodities. While there has been some deployment of white box SDN switches, that deployment has been limited. In addition to predicting that SDN would cause switches and routers to become commodities, for the first few years the discussion of SDN focused almost exclusively on its use in the data center. As discussed below, that conversation is changing.
