Abstract
This paper presents a Petri net approach to modeling and performance analysis of the Z39.50 Search and Retrieval protocol. The Z39.50 state tables present a complex set of events and actions. Based on these state tables, a Petri net model is for the first time constructed for the entire system comprising the protocol. A Reachability Graph analysis method is applied to the Petri net model to study the behavioral properties of the protocol. Assuming deterministic delays, time analysis is performed and completion times are computed for basic successful events and operations. A timed Petri net simulation tool is used to investigate the behavior of complex Z39.50 services and operations.