Automatic verification of interactions in asynchronous systems with unbounded buffers

Abstract

Asynchronous communication requires message queues to store the messages that are yet to be consumed. Verification of interactions in asynchronously communicating systems is challenging since the sizes of these queues can grow arbitrarily large during execution. In fact, behavioral models for asynchronously communicating systems typically have infinite state spaces, which makes many analysis and verification problems undecidable. In this paper, we show that, focusing only on the interaction behavior (modeled as the global sequence of messages that are sent, recorded in the order they are sent) results in decidable verification for a class of asynchronously communicating systems. In particular, we present the necessary and sufficient condition under which asynchronously communicating systems with unbounded queues exhibit interaction behavior that is equivalent to their interactions over finitely bounded queues. We show that this condition can be automatically checked, ensuring existence of a finite bound on the queue sizes, and, we show that, the finite bound on the queue sizes can be automatically computed.