The main purpose of this paper is to give a method forconstruction of the reduced reachability graph for Stochastic Petri Nets(SPN), the symbolic graph. This construction is achieved by exploitingthe structural symetries in the net using the theory of bisimulation ofplaces for detecting isomorphic parts in the net. The symbolic graph,being isomorphic to an agregated Markov chain, may be used to provequalitative properties as liveness, boundness, ... Moreover, thisreduced graph make more easy the computation of the performance measuresof interest as the mean number of tokens in a place, the mean number offiring transition ... We have so developped a tool, SSPN (StochasticSymetric Petri nets), for generating the symbolic graph and deducingqualitatives and quantitatives properties.
