The Competitive Nature Of Research, Complex Computer Network Systems

With the rapid development of computer science and communication technology in the recent decades,computer network systems,which come into being based on the computer system and communication system,show the increasingly complex characters. The Internet,Wide Area Network,Metropolitan Area Network,Local Area Network all present complex features,particularly the competition-cooperation feature.The contention-conflict issues of computer networks are discussed in this paper.The study includes the following five issues:Firstly,the complex features of the computer network systems,especially the competition character,are deeply discussed.It is conclude that the competition show universality and objectivity,whereas the cooperation show particularity and provisionality. According to the law of the competition character,the conflict resolution strategy can be improved to meet the objective demand,so that the competition can be solved to realize the order cooperation between members.Secondly,to resolve the Internet congestion result from competing network resources,a multi-priority dynamic threshold deployment—Preferential Dynamic Threshold RED and Optimized Preferential Dynamic Threshold RED algorithms are proposed.They can satisfy the lower loss rate of packets with high priority and high buffer utilization.Thirdly,based on OPNet modeler,the simulation for Contention-Collision Cancellation(C-CC) access control mode in multi-star LAN is implemented.Through the simulation modeling,The simulation result for typeⅠsingle-star LAN is compared with the mathematical result in previous reference;the performance of typeⅠ,typeⅢand typeⅤsingle-star LAN are evaluated;the typeⅠmulti-star LAN is also discussed.Fourthly,the typeⅠsystem model for double-star LAN based on heavy load is revaluated.During the past long period,the mathematical modeling researches for multi-star LAN have been focusing on single-star LAN,for which all models and performance evaluation of the Contention-Collision Cancellation(C-CC) access mode have already finished.The breakthrough of mathematical modeling for double-star LAN is very late because of difficulty in math aspect,and just deduced the mean waiting time of the customer generated by observing terminal A.In this paper,we select the terminal A without customer as observing object,then getτ_i which is the mean period from time point r to the end of service for the customer generated firstly by terminal A,on the condition that at observing time point r,there are i(i＞0) customers in system and no customer in observing terminal A.This paper consummates the mathematical model of typeⅠC-CC access mode for double-star LAN.Finally,for the first time,the case of 2 servers is introduced into the typeⅤsystem model of C-CC access control mode in this paper.The terminal A with customer is selected as the observing object,and the tme delay t_i is got.The parameter t_i is the mean period from the observing time point r to the time point when the customer of terminal A departs from system.,on the condition that at the time point r,there are i(i＞0, based on heavy load) customers in system.This is another creative research on the C-CC access mode for double-star LAN after the typeⅠdouble-star LAN.