Modeling And Analysis Of Switch And WRR Scheduling Algorithm Based On Petri Net

Petri net theory is a powerful tool for the research of systems performance analysis. Petri net not only has solid foundation of mathematics, but also holds lots of analysis softwares, and can be used in all kinds of fields as a modeling tool. As an important branch of Petri net, Generalized Stochastic Petri net can concisely describe the states and the variation process of systems, and has made great success in the modeling and performance analysis of complicated systems. The thesis gives the models of switch and weighted round robin scheduling algorithm, and analyzes their performance.Firstly, the theory of Petri net, timed Petri net, stochastic Petri net and generalized stochastic Petri net (GSPN) are dissertated with some examples in the second chapter. Furthermore, the second chapter introduces three analysis softwares which support Petri net. These softwares can help to understand Petri net, and have great value. The structure of the switch is described in detail in the third chapter. Secondly, the model of switch based on GSPN is given in the fourth chapter. The model is analyzed by the powerful software package --- TimeNET. The analysis results lay the groundwork for comprehending the structure of switch, and provide reference for future research about switched industrial Ethernet.The fifth chapter expatiates on weighted round robin(WRR) scheduling algorithm, and give an improved WRR algorithm, the minimum round WRR (MR-WRR), which is simple and easy to fulfill. Finally, the thesis creates models for WRR and MR-WRR, and by analyzing the both to get a conclusion that MR-WRR is better than WRR.