Articles

Decentralized control loops are widely credited with improving system resilience, on the reasoning that removing a central point of coordination also removes a central point of vulnerability. This article separates two properties that applied literature on decentralized architecture routinely conflates: bounded fault tolerance, the capacity of a control architecture to remain stable when an individual loop or node is switched off or corrupted in isolation, and network-level resilience, the capacity to recover from correlated disturbances such as communication loss, targeted compromise, or cascading propagation across dependency chains. Reviewing control-theoretic stability results alongside consensus and infrastructure-resilience research shows that the first property follows from specific, testable structural conditions: a steady-state gain condition in one case, a minimum-neighbor redundancy count in another. These conditions come in different strengths depending on whether the disturbance is benign disconnection or active compromise, a distinction the second property depends on and that decentralization leaves for the designer to resolve. The analysis concludes that a resilience claim attached to a decentralized control loop is a claim about a specific structural parameter matched to a stated disturbance model, a parameter whose verification requires evidence beyond the topology itself.