A Kind Of Fault-tolerant ATM Switch Research And Network System Simulation And Analysis Of Network System Security Scenario

This report is composed of three parts: the first one is the research of one kind of fault-tolerant ATM switch, the second is network system simulation and some cases, the last one is a security case of a network system.In this report, we discuss a kind of new fault-tolerant ATM switch. This switch improves the network dependability by the fault tolerance structure. The asynchronous transfer mode (ATM) is the transfer mode recommended for the broad integrated service digital network (B-ISDN) by ITU-T. Fault-tolerant is main method to enhance the network dependability. We first introduced the switch structure. This kind of switch structure increases the redundant paths by subswitches and extended links. This structure can tolerate multiple faults and the redundant paths increase exponentially as the size of the switch stages increases. We can gain the survival probability, level of fault tolerance and cost-effectiveness ratio of this switch by the simulation, and the simulation results indicate that the proposed architecture is more fault-tolerant and cost-effective than those architectures found in the literature. In Chapter One we first summarize the fault-tolerant electronic digital system, discuss the generation, development and sort of the fault tolerance and fault avoidance system, also the sort of the fault and the design of fault-tolerant system. In Chapter Two we dissertate the fault-tolerant ATM switch with subswitches and extended links. We gain the fault-tolerant performance and draw a conclusion by the theoretic analysis and simulation analysis.It needs experiments to study, analyze and design system. There are two methods, one is to work on the real system, and the other is that we first gain a model and study directly on the model. The later one is simulation. Network system simulation is to simulate a network system with discrete event system by Monte Carlo method. In Chapter Three We introduce some network simulation tools. In Chapter Four we discuss the significance, concept and characteristic of the network simulation. Then we introduce the steps of network simulation modeling. In the post doctor research four network system simulations are finished, we will analyze one of them that work with ns2 simulation tool and gain the conclusion.The network security and hacker problem become more and more attentive with the development of network technology and LAN, Intranet and Internet. Network managers pay more attention to network security. There must be bad loss if we ignore it. In Chapter Five, we bring forward the network security advice of one company, and discuss the network security system integration and service in detail.In Chapter Six there are the work summary of the post-doctor research.