Reducing energy consumption in SDN-based data center networks through flow consolidation strategies.

In the last decade we noticed a growth on studies regarding energy savings in data centers. The main reasons include political factors such as compliance with global protocols of conscious energy consumption, financial incentives such as tax reduction, and environmentally driven by concerns about sustainability issues such as emission of heat and gases harmful to the ozone layer. Most works aim to reduce the energy consumption of servers and cooling systems. However, network devices comprise also a significant slice of the total Data Center energy consumption, and most studies often neglect that. In this paper, we propose techniques to define flow paths in an SDN-based Data Center network respecting flow bandwidth requirements, while also enabling changing the operation state of network devices to a state of lower energy consumption in order to reduce the total consumption of the network layer. We evaluate the proposed techniques using different ratios of link demand oversubscription in a fat-tree topology with different POD sizes. Results show savings of up to 70% regarding energy consumption in the network layer.