Methodology for LAN modeling and analysis using Petri nets based models

The goal of this paper is to present a methodology for modeling and analyzing the main characteristics of time critical distributed systems. This methodology is presented through the study of the fieldbus FIP and is based on the use of two complementary Petri nets based models: the labeled predicate transition nets (LPrT) which are well adapted for representing complex communication systems, but which do not consider the time characteristics; and the stochastic timed Petri nets (STPN) which have the ability to express time constraints and are then well adapted for representing time critical systems. The analysis made with the LPrT model visualises all the possible different sequences of actions. The analysis made with the STPN model shows the discriminating power of time constraints and allows to make performance evaluations. The study concerns the behavior of an application layer producer entity providing a producer user process with variable writing services and mechanisms for the temporal validity of variable values