带宽非对称网络中TCP性能分析

Performance Analysis of TCP over Bandwidth Asymmetry Networks

考察了带宽非对称对基于端到端的 TCP协议性能的影响程度 .通过数学建模推导出了带宽大量对称情况下 TCP平均吞吐量的计算公式 ,并仿真验证了推导的有效性 .结果表明 ,在带宽非对称网络中 ,正向吞吐量的取得不仅依赖于正向的业务特性和链路的性能 ,而且在很大程度上取决于反向的业务特性和链路的性能 .结论是反向带宽和队列容量将使 TCP性能成非线性变化 .

The performance of TCP over bandwidth asymmetry networks is analyzed.With the definition of normalized bandwidth ratio, the formula to calculate the TCP throughput with asymmetrical bandwidth and infinite reverse buffer is deduced. Effectiveness of deduction is verified by simulation studies. In a network with asymmetry bandwidth, throughput achieved is not only dependent on the traffic and link characteristics of the forward direction, but also significantly determined by those of the backward direction. Through simulations and our deduction, we conclude that the TCP throughput is linear to the reverse bandwidth with infinite reverse buffer and nonlinear to that with finite reverse buffer.