应用于非对称网络的改进TCP Vegas 协议

华南理工大学学报（自然科学版） ›› 2007, Vol. 35 ›› Issue (1): 80-83,88.

应用于非对称网络的改进TCP Vegas 协议

刘靖陈芳炯韦岗

华南理工大学电子与信息学院，广东广州 510640

收稿日期:2006-03-13 出版日期:2007-01-25 发布日期:2007-01-25
通信作者: 刘靖(1973-) ，女，工程师，博士生，主要从事流量控制和IP QoS 方面的研究。 E-mail:liuj7@gdtel.com.cn
作者简介:刘靖(1973-) ，女，工程师，博士生，主要从事流量控制和IP QoS 方面的研究。
基金资助:
国家自然科学基金资助项目( 60402014) ;广东省自然科学基金资助项目(31390 )

Enhanced TCP Vegas Protocol for Asymmetric Networks

Liu Jing Chen Fang-jiong Wei Gang

School of Electronic and Information Engineering , South China Univ. of Tech. , Guangzhou 510640 , Guangdong , China

Received:2006-03-13 Online:2007-01-25 Published:2007-01-25
Contact: 刘靖(1973-) ，女，工程师，博士生，主要从事流量控制和IP QoS 方面的研究。 E-mail:liuj7@gdtel.com.cn
About author:刘靖(1973-) ，女，工程师，博士生，主要从事流量控制和IP QoS 方面的研究。
Supported by:
国家自然科学基金资助项目( 60402014) ;广东省自然科学基金资助项目(31390 )

摘要/Abstract

摘要： TCP Vegas 协议已被证明比传统TCP 协议性能优越，但在非对称网络中的性能不理想.文中提出针对这一缺陷的改进算法.首先基于确认包中的ecn_to_echo 位估计反向链路的拥塞概率，证明了拥塞概率和分组的环型流程时间(RTT) 成正比.接着，通过监测拥塞概率的变化，求出RTT 的变化，进而求得拥塞前的实际RTT ，并以此为基础执行TCP Vegas 流量控制协议.基于NS-2 的仿真实验表明，文中算法在正、反向链珞出现拥塞时的性能均优于现有Vegas 算法。

关键词: 流量控制, 非对称网络, TCP Vegas 协议

Abstract:

It has been proved that the TCP Vegas protocol underutilizes the available bandwidth in asymmetric net-worksalthough it possesses better performance than the traditional TCP protocol. In order to solve this problem , an enhanced TCP Vegas algorithm is proposed. In this algorithm , the ecn_to_echo_bits in the acknowledge packets are firsL used to estimate the congestion probability in the backward path , proving that the change of Round -Trip-Time (RTT) is directly proportional to the change of congestion probability. Then , when backward congestion occurs ,the change of RTT is estimated by monitoring the change of congestion probability. Thus , the actual RTT before the congestion is obtained , which is used to implement the TCP Vegas protocol. The simulations based on NS-2 show that the proposed algorithm is more applicable than the existing Vegas algorithm when the congestion occurs both in forward and backward paths.

Key words: flow control, asymmetric network, TCP Vegas protocol

刘靖陈芳炯韦岗. 应用于非对称网络的改进TCP Vegas 协议[J]. 华南理工大学学报（自然科学版）, 2007, 35(1): 80-83,88.

Liu Jing Chen Fang-jiong Wei Gang. Enhanced TCP Vegas Protocol for Asymmetric Networks[J]. Journal of South China University of Technology (Natural Science Edition), 2007, 35(1): 80-83,88.