Flow scheduling strategies for minimizing flow completion times in data center networks

Minimizing the flow completion time (FCT) is widely considered as an important optimization goal in designing data center networks. However, existing schemes either rely on the precondition that the size and deadline of each flow is known in advance, or require modifying the switch hardware, which is hard to implement in practice. In this paper, we present a flexible and dynamic flow scheduling strategy, namely, Maximal Completion Probability First (MCPF), to reduce the FCT. This strategy is based on the estimated probabilities of each flow to finish the transmission in a period time, and these flows which have higher completion probabilities are assigned with higher priority. Meanwhile, switches perform flow scheduling according to these priorities. We employ a queueing theory based mathematical model to analyze the average FCT of MCPF, and compare it with other two flow scheduling strategies. We also introduce the challenges and the solutions to implement MCPF in realistic networks. Finally, we evaluate the performance of MCPF in Mininet. The analysis and experimental results show that MCPF could effectively reduce the FCT.