Data center networks need to provide low latency, especially at the tail, as demanded by many interactive applications. To improve tail latency, existing approaches require modifications to switch hardware and/or end-host operating systems, making them difficult to be deployed. We present the design, implementation, and evaluation of RepNet, an application layer transport that can be deployed today. RepNet exploits the fact that only a few paths among many are congested at any moment in the network, and applies simple flow replication to mice flows to opportunistically use the less congested path. RepNet has two designs for flow replication: (1) RepSYN, which only replicates SYN packets and uses the first connection that finishes TCP handshaking for data transmission, and (2) RepFlow which replicates the entire mice flow. We implement RepNet on node.js, one of the most commonly used platforms for networked interactive applications. node's single threaded event-loop and non-blocking I/O make flow replication highly efficient. Performance evaluation on a real network testbed and in Mininet reveals that RepNet is able to reduce the tail latency of mice flows, as well as application completion times, by more than 50%.

中文翻译：

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RepNet：通过数据中心网络中的流复制减少延迟

数据中心网络需要提供低延迟，尤其是在尾部，这是许多交互式应用程序所要求的。为了改善尾部延迟，现有方法需要修改以切换硬件和/或终端主机操作系统，这使得它们难以部署。我们介绍了 RepNet 的设计、实现和评估，这是一种今天可以部署的应用层传输。RepNet利用网络中任何时刻只有少数路径拥塞的事实，并将简单的流复制应用于小鼠流，以机会性地使用拥塞较少的路径。RepNet 有两种流复制设计：(1) RepSYN，它只复制SYN 数据包并使用完成TCP 握手的第一个连接进行数据传输，以及(2) RepFlow，它复制整个鼠标流。我们在 node.js 上实现了 RepNet，node.js 是网络交互式应用程序最常用的平台之一。node 的单线程事件循环和非阻塞 I/O 使流复制非常高效。在真实网络测试平台和 Mininet 上的性能评估表明，RepNet 能够将鼠标流的尾部延迟以及应用程序完成时间减少 50% 以上。