Improved queue management algorithm based on NS2 and its implementation
HU Yong 1,LI Xunming 2,GAO Lisha1(1.Nanjing Power Supply Company of Jiangsu,Nanjing 210000,China; 2.Hohai University,Nanjing 210098,China)
Active queue management is an important congestion control mechanism,and its quality concerns the performance of whole network.The traditional PID controller has simple structure,good performance,but the parameters are fixed in whole process.The neuron can effectively overcome the disadvantages of PID controller in parameter adjustment and non-linear system.A single-neuron adaptive PID controller is presented,which is analyzed and tested in two aspects.Based on a developed dynamical model,which avoids TCP congestion,both the traditional PID controller and the improved controller are simulated in Matlab software environment and compared in queue length and data loss probability under the guidance of control theory.Without theoretic math model,the test platform is constructed using network elements of NS software,such as nodes,links,FTP service source,on which PI,PID and improved algorithms are applied to test system stability and adaptability by observing the changes in queue length and link number.Simulation results show the algorithm proposed better in stability,robustness and adaptability.
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