Dynamic Router's Buffer Sizing using Passive Measurements and P4 Programmable Switches
Dynamic Router's Buffer Sizing using Passive Measurements and P4 Programmable Switches
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DOI：
10.1109/globecom46510.2021.9685160
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发表时间：
2021-12
期刊：
影响因子：
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通讯作者：
Elie F. Kfoury;J. Crichigno;E. Bou-Harb;Gautam Srivastava
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文献类型：
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作者：
Elie F. Kfoury;J. Crichigno;E. Bou-Harb;Gautam Srivastava
路由器的缓冲区大小对网络的性能有着重要的影响。网络运营商现在手动和静态地配置路由器的缓冲区大小。它们通常会配置大型缓冲区，这些缓冲区会填满并且永远不会变空，从而显著增加数据包的往返时间（RTT）并降低应用程序性能。文献中很少有动态调整缓冲区大小的工作，但只在模拟器中实现，因此无法在具有真实的流量的生产网络中进行测试和部署。以前的工作建议将缓冲区大小设置为带宽延迟乘积（BDP）除以长流数量的平方根。当提前知道RTT和长流数量时，这样的公式是足够的。本文提出了一种系统，利用可编程开关作为被动仪器来测量RTT和计算流经传统路由器的流的数量。基于测量，可编程交换机动态地调整传统路由器的缓冲器大小，以便减轻不必要的大排队延迟。实验结果表明，动态调整缓冲区可以提高长流之间的RTT、丢包率和公平性。此外，共享队列的短流的流完成时间（FCT）大大改善。该系统可用于校园、企业和服务提供商网络，无需更换传统路由器。
The router's buffer size imposes significant impli-cations on the performance of the network. Network operators nowadays configure the router's buffer size manually and stati-cally. They typically configure large buffers that fill up and never go empty, increasing the Round-trip Time (RTT) of packets significantly and decreasing the application performance. Few works in the literature dynamically adjust the buffer size, but are implemented only in simulators, and therefore cannot be tested and deployed in production networks with real traffic. Previous work suggested setting the buffer size to the Bandwidth-delay Product (BDP) divided by the square root of the number of long flows. Such formula is adequate when the RTT and the number of long flows are known in advance. This paper proposes a system that leverages programmable switches as passive instruments to measure the RTT and count the number of flows traversing a legacy router. Based on the measurements, the programmable switch dynamically adjusts the buffer size of the legacy router in order to mitigate the unnecessary large queuing delays. Results show that when the buffer is adjusted dynamically, the RTT, the loss rate, and the fairness among long flows are enhanced. Additionally, the Flow Completion Time (FCT) of short flows sharing the queue is greatly improved. The system can be adopted in campus, enterprise, and service provider networks, without the need to replace legacy routers.