Passive estimation of TCP round-trip times
Passive estimation of TCP round-trip times
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DOI：
10.1145/571697.571725
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发表时间：
2002-07
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通讯作者：
Hao Jiang;C. Dovrolis
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文献类型：
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作者：
Hao Jiang;C. Dovrolis
我们提出并评估了一种被动测量方法，该方法估计了流经网络链路的TCP连接的往返时间（rtt）分布。这种RTT分布在缓冲区供应、主动队列管理的配置和检测无响应流量的拥塞方面非常重要。所提出的方法基于两种技术。第一种技术适用于TCP调用方到被调用方流，它基于3路握手消息。第二种技术适用于调用方到调用方流，当被调用方向调用方传输大量MSS段时，它基于TCP的慢启动阶段。在我们检查的跟踪中，完整的估计算法报告了55-85% TCP工作负载的RTT（以字节计）。验证实验表明，大约90%的被动测量值在ping测量的RTT的10%或5ms（以较大者为准）范围内。此外，对几个NLANR跟踪的测量表明，对于70-80%已处理的TCP连接，这两种估计技术在25毫秒内一致。我们还将估计方法应用于一些NLANR轨迹，并检查了测量的RTT分布在短时间尺度和长时间尺度上的变异性。
We propose and evaluate a passive measurement methodology that estimates the distribution of Round-Trip Times (RTTs) for the TCP connections that flow through a network link. Such an RTT distribution is important in buffer provisioning, configuration of active queue management, and detection of congestion unresponsive traffic. The proposed methodology is based on two techniques. The first technique is applicable to TCP caller-to-callee flows, and it is based on the 3-way handshake messages. The second technique is applicable to callee-to-caller flows, when the callee transfers a number of MSS segments to the caller, and it is based on the slow-start phase of TCP. The complete estimation algorithm reports an RTT for 55-85% of the TCP workload, in terms of bytes, in the traces that we examined. Verification experiments show that about 90% of the passive measurements are within 10% or 5ms, whichever is larger, of the RTT that ping would measure. Also, measurements on several NLANR traces show that the two estimation techniques agree within 25ms for 70-80% of the processed TCP connections. We also apply the estimation methodology on a number of NLANR traces and examine the variability of the measured RTT distributions in both short and long timescales.