Research On Intelligent Congestion Control Mechanism Of Multilevel Network Nodes

Computer network is an important landmark into information generation, and it has comprehensively changed human being's life and work styles. Researching on network model and control algorithm, reducing network congestion and packets transmission time-delay, strengthening transmission efficiency, and improving communication quality for users are the goals that we are always pursuing in the area of Information Technology.The paper expounds the development of various congestion control mechanism, analyzes the theory of congestion control, essentializes the present the network simulation technology and introduces the simulation software--OPNET which is used in simulation testing in short.Then the paper illustrates the modeling principle and process of the network simulation, studies the simulation model based on real object, finds the mapping relationship of fact network and simulation model, and gives the basal structure of three layers network simulation model which is made up of network region,nodes region and process region.The paper illustrates the simulation model and the experiment analyse of counting simple package. A multilevel network node model is designed and the control mechanism based on multilevel network nodes is proposed according to complicated network structure. By the characteristics of every level source, the exprement analyse of the multilevel network node model are given in this paper,chooseing probability drop strategy and BP neural network (NN) PID control mechanisms. And online simulation based on OPNET show good performance of three proposed control mechanisms. At last, author studies and compiles direct network simulation software under the WINDOWS platform which is based on SOCKET interface. The simulation process of the software is realized in real datagram of local networks, validates that PID control mechanisms can resolve congestion problem in a certain extent. It has practical significance.Lying on the Field Bus Technology & Automation the key lab of Beijing, using the tool of control theory and OPNET network simulation software, supported by open foundation and Sun Dehui processor' elaborate guide, my research focuses on network congestion avoidance, a large quantity of research is done and some achievement has been attained.