计算机应用 ›› 2011, Vol. 31 ›› Issue (09): 2344-2348.DOI: 10.3724/SP.J.1087.2011.02344

• 网络与通信 • 上一篇    下一篇

基于非线性窗口增长的TCP Westwood改进算法

赵文波1,孙小科2,马草川2   

  1. 1. 天水师范学院 物理与信息科学学院,甘肃 天水 741000
    2. 天水师范学院 数学与统计学院,甘肃 天水741000
  • 收稿日期:2010-12-09 修回日期:2011-01-23 发布日期:2011-09-01 出版日期:2011-09-01
  • 通讯作者: 赵文波
  • 作者简介:赵文波(1978-),男,甘肃陇南人,助教,硕士,主要研究方向:网络拥塞控制、网络QoS体系;
    孙小科(1981-),男,甘肃平凉人, 讲师, 硕士, 主要研究方向:非线性系统稳定性;
    马草川(1981-),男,甘肃天水人, 讲师, 硕士, 主要研究方向:非线性系统稳定性。

Enhanced TCP Westwood algorithm based on nonlinear congestion window increase

ZHAO Wen-bo1,SUN Xiao-ke2,MA Cao-chuan2   

  1. 1. School of Physics and Information Science, Tianshui Normal College, Tianshui Gansu 741001, China
    2. School of Mathematics and Statistics, Tianshui Normal College, Tianshui Gansu 741001, China
  • Received:2010-12-09 Revised:2011-01-23 Online:2011-09-01 Published:2011-09-01
  • Contact: ZHAO Wen-bo

摘要: TCP Westwood(TCPW)算法在拥塞避免阶段拥塞窗口采用线性增长方式,不利于快速获得高吞吐量和维持高吞吐量。该算法在慢启动阶段仍然采用指数增长模式,从而导致大量突发数据的产生,造成拥塞。针对以上不足,提出了改进算法——NLTCP Westwood(NLTCPW)。该算法在慢启动阶段发送窗口较TCPW算法能更快地到达10个包左右,之后窗口增长速度较TCPW算法则有所减慢;而在拥塞避免阶段采用基于当前拥塞窗口大小的先快后慢的非线性增长方式。数学模型分析和仿真结果表明,NLTCPW算法在高速网环境下的性能较TCPW更好,具有较好的吞吐量、稳定性、友好性和较低的丢包率。

关键词: 拥塞窗口, 高速网, 吞吐量, 非线性方式, 慢启动, 稳定性, 公平性, 友好性

Abstract: Congestion window of TCP Westwood (TCPW) is based on the increase of linear mode at the congestion avoidance phase in high-speed networks. Therefore, it cannot rapidly obtain or maintain the high throughput. During the slow-start stage, the congestion window of TCPW is based on exponential growth mode, which will cause the datagram increases too fast and prompt the probability of congestion. For the above defects, TCPW was improved from two aspects, and the new algorithm was called NLTCPW. During the slow-start stage, send window of NLTCPW got 10 packets faster than TCPW. After that, the increment speed of send window was decelerated. A simple nonlinear mode was used to increase the congestion widow at the congestion stage. The performance analysis of mathematical model and simulation results show that NLTCPW algorithm has better throughput performance, lower packet loss rate and better fairness, and it is friendly and stable in high-speed networks.

Key words: congestion window, high-speed network, throughput, nonlinear mode, slow-start, stability, fairness, friendliness

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