AAC: Adaptively Adjusting Concurrency by Exploiting Path Diversity in Datacenter Networks

Recent datacenter load balancing designs make full use of all available multiple paths to achieve high bisection bandwidth and support the increasing traffic demands. However, a multitude of uncertainties, such as congestion and asymmetry, easily leads to long tailed latencies for unlucky flows on bad paths. In this paper, we aim at adjusting the maximum number of multiple paths used by existing load balancing designs to achieve good tradeoff between the tailed latency and link utilization. Specifically, we propose a packet-level load balancing called scheme Adaptively Adjusting Concurrency (AAC) to spread packets across the multiple paths, which are adaptively selected according to path diversity. AAC is deployed at switch, without any modifications on end-hosts. The experimental results of NS2 simulation and Mininet implementation show that AAC significantly reduces the flow completion time by ∼ 21–56% over the state-of-the-art datacenter load balancing designs including MPTCP, LetFlow and RPS.