Randomizing TCP payload size for TCP fairness in data center networks
Randomizing TCP payload size for TCP fairness in data center networks
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DOI：
10.1016/j.comnet.2017.09.007
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发表时间：
2017-12
期刊：
影响因子：
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通讯作者：
Soojeon Lee;Dongman Lee;Myungjin Lee;H. Jung;Byoung-Sun Lee
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文献类型：
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作者：
Soojeon Lee;Dongman Lee;Myungjin Lee;H. Jung;Byoung-Sun Lee
由于数据中心网络中多对一的流量模式，TCP流在共享瓶颈带宽时往往会遇到严重的不公平性，这就是所谓的TCP排斥问题。TCP丢弃问题的原因是丢弃尾队列引起的突发性数据包丢失，这会触发TCP超时并导致拥塞窗口减小。本文提出了一种传输层解决TCP流播问题的方案TCPRand。TCPRand的主要思想是随机化TCP负载大小，打破来自不同输入端口的流之间的同步数据包到达。基于当前拥塞窗口大小和CUBIC的拥塞窗口增长函数，TCPRand自适应地确定适当的随机性水平。通过大量的NS-3仿真和实验，我们证明了TCPRand即使在发生严重TCP丢弃的环境中，也能通过显著减少TCP超时时间来保证TCP公平性的上级增强. TCPRand还最小化总有效吞吐量损失，因为其自适应机制避免了不必要的有效载荷大小随机化。与DCTCP相比，TCPRand性能较好，只需要在发送端的传输层进行修改，部署相对容易。
As many-to-one traffic patterns prevail in data center networks, TCP flows often suffer from severe unfairness in sharing bottleneck bandwidth, which is known as the TCP outcast problem. The cause of the TCP outcast problem is the bursty packet losses by a drop-tail queue that triggers TCP timeouts and leads to decreasing the congestion window. This paper proposes TCPRand, a transport layer solution to TCP outcast. The main idea of TCPRand is the randomization of TCP payload size, which breaks synchronized packet arrivals between flows from different input ports. Based on the current congestion window size and the CUBIC’s congestion window growth function, TCPRand adaptively determines the proper level of randomness. With extensive ns-3 simulations and experiments, we show that TCPRand guarantees the superior enhancement of TCP fairness by reducing the TCP timeout period noticeably even in an environment where serious TCP outcast happens. TCPRand also minimizes the total goodput loss since its adaptive mechanism avoids unnecessary payload size randomization. Compared with DCTCP, TCPRand performs fairly well and only requires modification at the transport layer of the sender which makes its deployment relatively easier.