Formal Verification and Simulation for Performance Analysis for Probabilistic Broadcast Protocols

This paper describes formal probabilistic models of flooding and gossiping protocols, and explores the influence of different modelling choices and assumptions on the results of performance analysis. We use Prism, a model checker for probabilistic systems, for the formal analysis of protocols and small network topologies, and use in addition MonteCarlo simulation, implemented in Matlab, to establish if the results and effects found during formal analysis extend to larger networks. This combination of approaches has several advantages. The formal model has well defined synchronization primitives with clear semantics for modelling synchronous and asynchronous communication between nodes. Model checking of the probabilistic model determines exact probabilities and performance bounds, results that cannot be obtained by simulation, and even if the model is non-deterministic. The Monte-Carlo simulation can then be used to study effects that only emerge in larger networks, such as phase transition.