关键词: 路由器 拥塞控制 随机早期检测 NS2

Abstract:

The paper first analyses the design principle and algorithm implementation of the RED congestion control mechanism in touters, describes the defects of RED, and presents an improved adaptive algorithm D-RED. It sets a target value of average queue sizes, makes the maximal drop probability dynamically  minus or plus a value, which is educed by mathematical methods, correlative to the former drop probability when the instantaneous average queue length i  s less or larger than the value of the target average queue. Then the paper designs many experiments to compare the performances of the RED and D-RED al  gorithms based on NS2. Finally, the paper analyses and compares the simulation results about the performance standards such as throughput, delay, variat ion, packets drop ratio, etc. It is concluded that D-RED can reduce the drop probability by 15. 7% and the throughput by 9.4,1% compared with RED. To so me degree, TCP streams are protected so that they share fair network resources under D-RED,

Key words: （router, congestion control, random early detection, NS2）