Modeling ATM systems with GSPNs and SWNs

This paper overviews the work of the authors in the field of modeling and analysis of Asynchronous Transfer Mode (ATM) networks using Generalized Stochastic Petri Nets (GSPN) and a special class of high-level stochastic Petri nets known as Stochastic Well-formed Nets (SWN). These formalisms are first shown to be adequate tools for the development of models of ATM systems, provided that only one timed transition is used, together with many immediate transitions. The only timed transition in the GSPN and SWN models represents the ATM systems cell time, while immediate transitions implement the ATM systems behavior. The firing time distribution of the only timed transition is irrelevant for the computation of several interesting performance indices. The results, as well as the problems, derived from the analysis of ATM switches and Local Area Networks (LAN) that adopt the Available Bit Rate (ABR) service category are summarized and discussed, providing references to the works containing the technical details.