Parameterized Analysis of Reconfigurable Broadcast Networks

Abstract

Reconfigurable broadcast networks (RBN) are a model of distributed computation in which agents can broadcast messages to other agents using some underlying communication topology which can change arbitrarily over the course of executions. In this paper, we conduct parameterized analysis of RBN. We consider cubes, (infinite) sets of configurations in the form of lower and upper bounds on the number of agents in each state, and we show that we can evaluate boolean combinations over cubes and reachability sets of cubes in . In particular, reachability from a cube to another cube is a -complete problem.To prove the upper bound for this parameterized analysis, we prove some structural properties about the reachability sets and the symbolic graph abstraction of RBN, which might be of independent interest. We justify this claim by providing two applications of these results. First, we show that the almost-sure coverability problem is -complete for RBN, thereby closing a complexity gap from a previous paper [3]. Second, we define a computation model using RBN, à la population protocols, called RBN protocols. We characterize precisely the set of predicates that can be computed by such protocols.

Parameterized Broadcast Networks with Registers: from NP to the Frontiers of Decidability

“…Parameterized verification problems over RBN have been the subject of extensive study in recent years, concerning for instance reachability questions [5,11], liveness [9] or alternative communication assumptions [4]; however, RBN have weak expressivity, in particular because agents are anonymous. In [10], RBN were extended to BNRA, the model studied in this article, by the addition of registers allowing processes to exchange identifiers.…”