Modeling And Analysis Of Ethernet And CAN Bus With DSPN

Petri net theory is a powerful tool for the research of discrete event dynamic system.As an important branch of Petri net, deterministic and stochastic Petri net can conciselydescribe the states and the variation process of the DEDS, and has made great success inthe modeling and performance analysis of complicated systems. The thesis carries out theresearch about the implementation of DSPN software. What's more, the DSPN models ofsome network systems are presented and relative performance analysises are given.Firstly, the theory of generalized stochastic Petri net (GSPN), deterministic andstochastic Petri net are dissertated with some examples, based on which, the functionrequirement analysis and the general structure of DSPNAnalyzer, which is a softwaresystem, are designed. Then the functions of graph-tool module and solution module areimplemented in Visual C++ 6.0 developing environment with the method ofobject-oriented analysis and design. Until now, the system has capability of logicverification of DSPN model.Secondly, on the basis of widely used LAN technology—Ethernet, the thesis makesa critical analysis of the mechanism of Ethernet MAC layer—CSMA/CD+DR, then thesingle DSPN model and the compact DSPN model are established. With the powerfulanalysis tool—DSPNexpress-NG, a detailed analysis of the compact model is carried out,then the performance curves of throughput, average packet delay and retransmission rateare given. From different aspects, the data disclose the probabilistic law of the mainperformance index of Ethernet, and these laws provide a quantiztion proof to the Ehternetnetwork establishment.Finally, the thesis makes a critical analysis on the mechanism of CAN MAC layer—CSMA/CD+CR, based on which, a compact DSPN model of multiple nodes is presented.In the model, on the base of the priority of the examining node, different nodes ofdifferent priority are divided into three classes—High, Medium and Low priority. Thismethod diminishes the reachable marking of the system greatly;preventing the systemfrom state space explosion. On the analysis of the model, the performance curves ofthroughput, average packet delay and success transmission probability are gained, whichdisclose the operating regulations and provide a reference for the CAN systemestablishment.