TCP Vegas is a kind of congestion control algorithm designed for wired network environment, but it has many problems in MA NET application. This paper presents a new algorithm named TCP Vegas-HA (TCP Vegas-Hops Adaptive) to improve the performance of TCP Vegas in MANET. This algorithm tests and obtains a group of optimal threshold value in different number of hops and node caches and uses them as empirical values, and introduces hops adaptive mechanism to new congestion control method. Also for the issue that the minimum round-trip time (baseRTT) can not accurately measure when the router changes, we present a new measurement method using these empirical values. Results of the simulation on the algorithm show that it has great adaptability against the variation of mobile network, and can effective ly increase the TCP Vegas throughput in MANET.%TCP Vegas是为有线网络设计的一种拥塞控制算法,在MANET下使用存在诸多问题.提出一种在MANET环境下提高TCP Vegas性能的新算法TCP Vegas-HA(TCP Vegas-Hops Adaptive),该算法通过测试获取一组不同跳数和节点缓存下的最优阈值作为经验值,在新的拥塞控制算法中引入跳数自适应机制,并针对路由改变时往返时间最小值baseRTT无法精确测量的问题,提出新的利用经验值的测量方法.对算法仿真执行的结果表明,该算法对网络环境的变化具有良好的适应性,能有效提高TCP Vegas在MANET中的吞吐量.
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