Traffic Consolidation for Green Optical DCNs

Present-day datacenter networks (DCNs) are designed to provide full-bisection bandwidth in order to support high network throughput and server agility. However, many studies have shown average utilization of the DCN is very low even at high server loads. As a result, there is a significant waste of energy resources in modern datacenters. In this paper we describe the construction and evaluation of a hardware device that consolidates traffic going between servers and the top-of-rack (ToR) switch. The consolidator operates entirely in the optical domain and has very low power consumption. We evaluate the performance of the consolidator in a small network. Subsequently, using simulations, we show that for larger systems, the consolidator allows energy savings of almost 70% at light loads and scales with increasing loads.