【摘要】 TCP在高带宽时延积网络中不能获得良好的性能,主要表现为低的吞吐量和大的窗口震荡.HSTCP算法解决了传统TCP算法在高带宽时延积网络下的性能瓶颈,但HSTCP在拥塞点时会产生大量的数据包丢失,同时当队列管理为去尾算法时,存在着严重的RTT不公平性问题.针对HSTCP算法的性能缺陷,该文提出一种在拥塞避免阶段进行拥塞避免模式切换的改进算法,称为EHSTCP.基于拥塞窗口历史值的端到端可用带宽预测方法,利用拥塞窗口历史信息来判断拥塞避免切换点.同时引入RTT公平因子,消除了HSTCP的RTT不公平性问题.NS2仿真实验验证了算法的有效性.更多还原

【Abstract】 TCP doesn’t perform well in high bandwidth-delay product networks,and its main limitations are low throughput and large oscillation of congestion window.HSTCP solves the primary limitations of regular TCP,but there exists large number of packet loss upon congestion epoch and serious RTT unfairness with drop-tail gateway.To overcome the above deficiency,this paper proposes an improved algorithm,called EHSTCP,which switches between two congestion avoidance modes in congestion avoidance phase.To locate the switch point,this paper presents a new prediction method for end-to-end available bandwidth using history congestion window dynamics.Simultaneously,it introduces the RTT fairness factor to eliminate the serious RTT unfairness in HSTCP.NS2 simulation results validate the effectiveness of the proposed scheme.更多还原