A Mechanism Achieving Low Latency for Wireless Datacenter Applications

Tao Huang1,2, Jiao Zhang1 and Yunjie Liu2

  1. State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications
    Beijing, P. R. China
    fhtao, jiaozhangg@bupt.edu.cn
  2. Beijing Advanced Innovation Center for Future Internet Technology
    Beijing 100124, China
    htao@bupt.edu.cn, liuyj@chinaunicom.cn

Abstract

Recently, several wireless/optical datacenter architectures are designed to overcome the drawbacks of wired datacenter topologies, such as expensive highend switches, high cabling complexity, congestion caused by a few hot nodes. Compared with wired switches, current commodity wireless switches usually suffer lower throughput as well as higher packet loss ratio and latency. However, todays datacenter applications, such as web search, require quite low latency to improve user experience. In this paper, a mechanism, named pECN, is proposed to achieve low latency for delay-sensitive flows. pECN makes use of Explicit Congestion Notification (ECN) to maintain a small queue length and a priority-based scheduling mechanism to provide delay differentiated services. The priority-based scheduling mechanism works at the packet level. When transmitting, the packet with the highest priority will be sent. Since the queue length is controlled within a small value by the ECN mechanism, the scheduling mechanism does not incur large overhead. Also, since it works at the packet level, it can support unlimited number of services. Besides, pECN does not need to maintain any flow state at switches. We implemented the proposed mechanism and evaluated the performance on the ns-2 platform. The simulation results show that pECN works better compared with TCP, DCTCP and D2TCP in terms of the flow completion time and the number of flows that can be supported without compromising deadlines.

Key words

datacenter network, latency, ECN, priority based scheduling

Digital Object Identifier (DOI)

https://doi.org/10.2298/CSIS160301020H

Publication information

Volume 13, Issue 2 (June 2016)
Year of Publication: 2016
ISSN: 1820-0214 (Print) 2406-1018 (Online)
Publisher: ComSIS Consortium

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How to cite

Huang, T., Zhang, J., Liu, Y.: A Mechanism Achieving Low Latency for Wireless Datacenter Applications. Computer Science and Information Systems, Vol. 13, No. 2, 639–658. (2016)