Analysis Of TCP/IP Network Congestion Principle And Research On Control Methods

With the rapid development of Internet, widespread use of computernetworks, as well as the appearance of varied network applications hasmade network congestion control a significant problem. The networkcongestion has become a bottleneck problem, which restricts thedevelopment and application of network. Congestion often results in thedecline of QoS (Quality of Service) parameters such as transmission delayand throughput, the network performance and resource utilization are alsoaffected seriously, effective QoS guarantee cannot be provided accordingly.Therefore, it is very important to solve the congestion problem effectivelyfor improving the network performance. How to avoid and control networkcongestion has become an active issue in the field of computer networkresearch.In chapter one, a general introduction of TCP/IP protocol and QoSrouting is given. The development of TCP/IP network congestion control is introduced in detail. The advantages and limitations of control theory used in congestion control are analyzed in the system aspect.Chapter two is the foundation of the whole thesis. Firstly, the cause and situation of current Internet network congestion are introduced. Secondly, various congestion control strategies of transport layer and network layer in TCP/IP protocol are analyzed detailedly. Finally, different control strategies are compared, the disadvantages of existed methods are discussed and improved proposals are presented.Chapter three is the emphasis of the thesis. Firstly, the fundamental concepts and principle of QoS routing including graph model of routing, status information and QoS routing strategies are introduced. Router congestion control strategies are also proposed. Secondly, a new multicast routing algorithm based on double chromosomes genetic algorithm is realized. The simulation results show that this algorithm can get better convergent effect and select best routing under proper system parameters. Finally, the multicast routing algorithm based on neural network is studied deeply, and the multicast routing algorithm based on chaotic neural network is presented. The simulation results show that this kind of algorithm can avoid getting into local minimum and improve convergent effect.In chapter four, the computer congestion control mechanism isanalyzed from the point of complicated system and control theory, the network congestion control system mathematical models are constructed, computer network system congestion control methods based on control theories such as PID and predictive control are researched.In chapter five, the whole study work of this dissertation is summarized and the prospect of solving the network congestion control problem based QoS is looked forward.Congestion control is a sophisticated task that cannot be absolutely resolved by a single protocol or an algorithm. The only way to guarantee the steadiness and efficiency of network is to use various strategies to control the congestion in multiple aspects of the whole network.