Congestion Control Improved Algorithm Of ATM Network Based On The Smith Principle

Now the ATM technology is mature day by day. Asynchronous Transfer Mode(ATM) is adopted as a typical technique by the International Telecommunication Union(ITU) and is spreaded . But the loss of data and the congestion of information are main reasons that affect the quality of service. ABR service is the only one type of traffic that can be controlled using the feedback mechanism. So, in the recent, the control and management of ABR service becomes a hot subject. The communication network is a large and hybrid system, the research on congestion control of ATM network has great significance in theory and practice. The paper is just based on it and the control theory is used to solve the congestion of controllable flow.The paper begins with the foundation of ATM network, and introduces the basic work principle of ATM networks. Type and parameters of business, ABR feedback mechanisms,RM cell format, ABR flow control targets.Then introduces congestion controls method: smith. Pointes out it's advantage and the shortcoming, Classical control theory and Smith's principle are applied in designing a class of effective and simple congestion control schemes for high-speed computer communication networks. Mathematical analyses verify the efficiency of the congestion control schemes. Come to the algorithm can reduce the buffer zone threshold. Additionally, used Smith congestion control research program to the single link of network model. Compare which is better of the two Smith congestion control through Simulation.This thesis aims at designing to the congestion control methods of ATM net- work ABR Service based on the smith principle. To overcome the shortcoming of the original Smith principle. Satisfying the actual demand of those ATM network which the link bandwidth is smaller relatively and the quality of service is higher.Compare with original control program, improved network control program can reduce the largest buffer queue amount.It can be applied to those networks that may have smaller bottleneck capacity.Prove the effectiveness of the network congestion control program which is improved. Improved congestion control program guarantee network formation's dynamic stability. Enhances the network transmission efficiency. Simultaneously guaranteed in the network transmission reduces the data missing as far as possible, that is advantageous to enhances the network performance.