On the performance analysis of ABR in ATM LANs with Stochastic Petri Nets

In this paper we use Generalized Stochastic Petri Nets (GSPNs) and Stochastic Well-formed Nets (SWNs) for the performance analysis of Asynchronous Transfer Mode (ATM) Local Area Networks (LANs) that adopt the Available Bit Rate (ABR) service category in its Relative Rate Marking (RRM) version. We also consider a peculiar version of RRM ABR called Stop & Go ABR; this is a simplified ABR algorithm designed for the provision of best-effort services in low-cost ATM LANs, according to which sources can transmit only at two different cell rates, the Peak Cell Rate (PCR) and Minimum Cell Rate (MCR). Results obtained from the solution of GSPN models of simple ATM LAN setups comprising RRM or Stop & Go ABR users, as well as Unspecified Bit Rate (UBR) users, are first validated through detailed simulations, and then used to show that Stop & Go ABR is capable of providing good performance and fairness in a number of different LAN configurations. We also develop SWN models of homogeneous ABR LANs, that efficiently and automatically exploit system symmetries allowing the investigation of larger LAN configurations.