Fault-tolerant multiprocessor system routing using incomplete diagnostic information

Fault-tolerant routing algorithms in multiprocessor systems utilize diagnostic information in selecting paths for messages. In many situations, only incomplete, or partial, diagnostic information is available for this purpose. The authors present algorithms for achieving two forms of diagnosis, known as k-reachability diagnosis and k-neighborhood diagnosis which provide partial diagnostic information. They compare, both analytically and through experiments conducted on an Intel iPSC/2 hypercube the performance and overhead of these two algorithms. They also present a routing algorithm that successfully routes messages between connected non-faulty nodes in systems of arbitrary topology containing an arbitrary number of faults. The performance of the algorithm is shown to be optimal when k= n-1 and within a factor of two of optimal, in the worst case, when k=1