Omco: Online Multiple Coflow Scheduling In Optical Circuit Switch

Coflow is gradually prevalent as a new traffic structure in data centers, which allows applications to convey their application-level semantics into the network. Meanwhile, optical circuit switches (OCS) are increasingly deployed in data centers due to the superiority in hardware, such as high bandwidth and low energy consumption. However, few works in the literature considered both coflow scheduling with OCS. In this paper, we study the coflow scheduling problem in an OCS-based data center network, with an aim to minimize the coflow completion time (CCT). We derive an online algorithm called OMCO to solve this problem. OMCO can not only optimize the circuit utilization but also minimize the number of circuit reconfigurations. Extensive simulations with real-world data traces show that OMCO outperforms other existing solutions dramatically. Compared with a FIFO-based scheme and the shortest-coflow-first heuristic, OMCO reduces the average coflow completion time by up to 61% and 62%, respectively.