Distributed on-line diagnosis in the presence of arbitrary faults

This paper introduces a new fault model for system-level diagnosis and a class of online distributed diagnosis algorithms that operate correctly in the presence of fault nodes that disseminate arbitrarily corrupted diagnostic information. The fault model addresses the practical issue of designing an internode test to cover diagnosis algorithm operation. Since an explicit test to detect arbitrary failures is not practical, evidence of a node´s faulty behavior is provided by examining diagnositic messages exchanged by the node. In many practical systems, algorithm overhead using the new fault model is only twice that required for algorithms using the PMC fault model. The key results include a description of the new fault model, the specification of a class of online distributed diagnosis algorithms that use this fault model, and proofs of their correctness.