Verification of Communication Protocols Using Abstract Interpretation of FIFO Queues

We address the verification of communication protocols or distributed systems that can be modeled by Communicating Finite State Machines (CFSMs), i.e. a set of sequential machines communicating via unbounded FIFO channels. Unlike recent related works based on acceleration techniques, we propose to apply the Abstract Interpretation approach to such systems, which consists in using approximated representations of sets of configurations. We show that the use of regular languages together with an extrapolation operator provides a simple and elegant method for the analysis of CFSMs, which is moreover often as accurate as acceleration techniques, and in some cases more expressive. Last, when the system has several queues, our method can be implemented either as an attribute-independent analysis or as a more precise (but also more costly) attribute-dependent analysis.