Fault-tolerant wormhole routing in torus networks with overlapped block faults

A fault-tolerant routing algorithm for torus networks that uses only three virtual channels is presented. The proposed algorithm is based on the block fault model, which is suitable for modelling faults at the board level in networks with grid structures. Messages are routed via shortest paths when there are no faults. However, if a message is blocked by a faulty block, the message will use a detour path to route around the faulty block. Previously at least six virtual channels were needed to achieve the same fault-tolerant ability. Simulation results using various workloads and fault patterns are presented.