In typical data center networks, an overwhelming majority of the flows are smaller than 200 KB in size, while most transmitted bytes are from a small fraction of large flows. The small flows are usually from the applications interacting with end users, thus they require small completion times. Meanwhile, the data center owners hope to keep the high throughput of the network to make full use of their investments on the network devices. To reduce the completion times of small flows while maintaining the high throughput of the network, we propose a novel transport algorithm, SCT (Transport with Slight Congestion), in this paper. SCT gives small flows higher priority by increasing their congestion windows at a higher rate. Moreover, SCT keeps the network to be in high utilization, thus the throughput of network is guaranteed. Extensive simulations show that SCT can reduce the average completion time of small flows by up to 48% at the expense of degrading the throughput of network by 5% only, compared with DCTCP.
['Zongyi Zhao', 'Qing Li', 'Mingwei Xu', 'Xingang Shi', 'Han Zhang']
Reduce completion time and guarantee throughput by transport with slight congestion