DREAM: DistRibuted Energy-Aware traffic Management for Data Center Networks

Traffic consolidation has been proposed to save energy in data center networks. However, existing centralized traffic consolidation approaches focus on achieving optimal network energy saving, without considering the need to be responsive to traffic variability. In this paper, we present DREAM, a distributed flowlet-level traffic consolidation framework for achieving energy efficiency in data center networks. DREAM splits a TCP flow across multiple paths based on ECN feedback by adapting the path selection probability for sending a flowlet. This helps to choose a path while avoid congestion/queue build-up at switches. Distributed agents in DREAM are implemented in Open vSwitch at each server without modifying applications, TCP, or the hardware switches in the data center network. Testbed evaluations using traces from Wikipedia web service and Facebook MapReduce traffic prove that DREAM on average achieves at least 15.8% energy saving for the data center network, while state-of-the-art approaches such as CARPO and ElasticTree produce 11.6% and 8.4% energy saving, respectively. The packet drop ratio in DREAM is less than 0.01% while the best among the alternatives, ElasticTree, has at least 0.19% drop ratio. DREAM also has 30% lower application-level latency than state-of-the-art centralized traffic consolidation approaches.