摘要
通过平面图形和建模的方法,分析了传输控制协议(TCP)拥塞控制中的网络往返时间(RTT)公平性.对于瓶颈链路,如果采用主动队列管理(AQM),两个竞争的TCP数据流流量比值近似为RTT比的倒数,存在RTT不公平性;如果采用弃尾队列管理,只有在不发生数据包超时的情况下,才出现明显的RTT不公平性,如果出现数据包发送超时,则情况较为复杂,频繁出现RTT大的TCP数据流多占用网络带宽的现象,因此很难得到一般性的结论.最后通过NS2仿真来验证所建模型和分析方法的正确性.
RTT(round-trip time) fairness in TCP(transmission control protocol) congestion control is analyzed by means of flat graphics and modeling.For the bottleneck link,if using active queue management(AQM),the flow ratio of the two competing TCP traffic streams is approximately the inverse of the RTT ratio,then the RTT unfairness exists.Otherwise,if using drop tail queue management,the obvious RTT unfairness will appear only in the case that the data packets do not time out.If the sending of the packets times out,it will be more complex,that is,large TCP flows of RTT will occupy the network bandwidth,and it is difficult to get a general conclusion.Finally,the NS2 simulations indicate the correctness of the model and the analysis method.
出处
《信息与控制》
CSCD
北大核心
2011年第5期680-685,共6页
Information and Control
基金
国家自然科学基金资助项目(60974129
60974013
70931002)
江苏省自然科学基金资助项目(BK2009388)
关键词
公平性
网络拥塞控制
拥塞窗口
主动队列管理
弃尾
fairness
network congestion control
congestion window
active queue management(AQM)
drop tail