## NS2基于控制原理的网络拥塞控制设计

Title   Internet congestion control algorithms based on   control theory
Abstract
With the fast development of the Internet, congestion control of the internet has played a more and more important role nowadays. It has developed from the traditional end-to-end TCP traffic control to queue management algorithms involving nodes on line. The active queue management(AQM) algorithms have drawn attention from the world in recent years.

This article introduces the priciples of RED algorithms then improve the calculating methods and propose Gentle-RED algorithms after reviewing the development of network congestion control algorithms. Later, we introduce the theory of control and study another algorithm named PI and use bilinear transformation to get the digital controller to make it more suiltable to the simulation environment.Next,we write the algorithm of PID to enlarge the queue management algorithms.
In the end, we introduce one popular network simulation software called NS2 and run simulations on it.Based on the analysis of tracing files,we get some pictures to compare the characters of above algorithms.We also point out directions for further study.
Keywords network congestion control  active queue management  RED  Gentle-RED       PI  PID

1  引言 1
2  RED算法及Gentle-RED算法 4
2.1   RED算法概述 4
2.2   RED算法分析 6
2.3  Gentle-RED算法概述 6
2.4  RED及其改进算法性能分析 7
2.5  本章小结 7
3  PI及PID主动队列管理算法 8
3.1  PI控制器原理   8
3.2  PI控制器的设计 8
3.3  PID控制其原理 10
3.4  PID系统的设计10
3.5  本章小结  12
4   仿真实验设计13
4.1  NS2简介 13
4.2  仿真网络的构建  14
4.3  本章小结  22

1  引言
1.1研究背景

①链路带宽不足。当多条输入链路的带宽总和大于输出链路的带宽总和时，到达的数据远远大于离开的数据，而当到达的数据排队超过队列缓冲区的长度时，就会造成网络拥塞。 NS2基于控制原理的网络拥塞控制设计:http://www.lwfree.cn/tongxin/20190113/29471.html
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