Congestion-aware adaptive forwarding in datacenter networks

Datacenters employ the scale-out model to achieve scalability. This model requires parallelism in the underlying workload. Therefore, high bisection bandwidth is required to support intensive communications between servers. Several new datacenter architectures have been designed to provide redundant bandwidth. Currently, it is critical to design a mechanism to efficiently utilize the abundant bandwidth. In this paper, we propose a distributed Congestion-Aware Adaptive foRwording (CAAR) protocol to balance traffic load only depending on the local queue length information. CAAR allows flows to select under-utilized paths to forward packets. It is theoretically proved to be stable if the arrival rates are within the network throughput region. Simulation results under diverse datacenter topologies and communication patterns validate that CAAR achieves higher aggregate goodput compared with random and static routing protocols. (C) 2015 Elsevier B.V. All rights reserved.