Petri Net Simulation of Computer Communications Systems

[摘要] This thesis presents the design of a simulation method for computer networking systems using timed Petri Nets along with the development of a simulation program based on this method. The use of this simulation program to evaluate the performance of a number of communications systems is described and its suitability as a general-purpose performance evaluation tool for networking systems is discussed. The development of the simulation method arose from the installation within Glasgow Royal Infirmary of a communications network for the transmission of digitised electrocardiograms. This was part of an ongoing project to develop a program for the automatic analysis of electrocardiograms by computer. The networking methodology currently in use on this network was developed using the simulation program. The aim in designing the simulator was to develop a tool which would be of use in simulating as wide a range of systems as possible and to this end a class of Petri net was developed which had a wide range of simulation capabilities, it was further intended that any extensions to the "Classical" Place/Transition net model should be made in such a way that the simplicity of the original model was preserved in as large a measure as possible. During the course of this work, various extensions to the basic Place/Transition net model were indeed made in order to increase the power of the simulation program. Some of these extensions are believed to be unique to the present program, in particular the use of a timed-place scheme. Most current work on timed Petri nets concentrates on timed-transition models as these are easier to implement and analyse; this thesis seeks to show that a timed-place model is viable as a simulation tool and is in many ways preferable to the timed-transition model. To test the range of the simulator, two extra simulation experiments were undertaken in addition to the simulation of the Royal Infirmary network, the first being the evaluation of a simple queueing system and the second the simulation of an Ethernet network. The simulation of the Ethernet network also tested the capability of the timed-place model to handle stochastic Petri net simulations, a type of simulation which is being used increasingly to model computer and networking systems and which is currently dominated by timed-transition models. Descriptions of all three simulation projects are presented along with an analysis of the results of each.

[发布机构] University:University of Glasgow

[关键词] Computer science