Stochastic model for data center energy saving augmented by optical wireless links

Data Centers (DC) consume an enormous amount of energy, now accounting for about 1.5% of US electrical usage. However, part of this energy (server operation and cooling) can be saved by turning off idle servers. This can be achieved by rerouting workloads from partially loaded servers, and thus allowing additional idle servers to shut down. Workload rerouting could be done by optical wireless communication (OWC) links, which can be deployed on top the existing cable/fiber network. In comparison to classic wired infrastructure, OWC deployment and maintenance is faster and simpler, and it offers dynamic configuration of the network. In this paper we derive a stochastic model of data center energy reduction using optical wireless links as a function of the data center load. Our results indicate that for typical data center energy reduction of more than 5% could be achieved for given set of parameters.