Analysis of data center SDN controller architectures: Technology and business impacts

The typical Software Defined Networking (SDN) Data Center (DC) of the future will likely be comprised of a software overlay and a hardware underlay, i.e., a physical network. From an architectural perspective, there are two distinct possibilities for such DCs. The first is a loosely coupled model where the software overlay and the hardware underlay are kept independent and managed separately. In this model, the software overlay is transparent and virtually invisible to the hardware underlay. The second is a tightly coupled model, where the software overlay and the hardware underlay work in cooperation, with the hardware underlay having visibility into the software overlay. This paper analyzes the impact of these approaches from a technology and business standpoint. It also presents some fundamentally different ideas for maximizing the value of the underlay in a Commercial-off-the-shelf (COTS) ASICs environment.