Fault-tolerant routing in mesh architectures

It is important for a distributed computing system to be able to route messages around whatever faulty links or nodes may be present. We present a fault-tolerant routing algorithm that assures the delivery of every message as long as there is a path between its source and destination. The algorithm works on many common mesh architectures such as the torus and hexagonal mesh. The proposed scheme can also detect the nonexistence of a path between a pair of nodes in a finite amount of time. Moreover, the scheme requires each node in the system to know only the state (faulty or not) of each of its own links. The performance of the routing scheme is simulated for both square and hexagonal meshes while varying the physical distribution of faulty components. It is shown that a shortest path between the source and destination of each message is taken with a high probability, and, if a path exists, it is usually found very quickly