Fault-tolerant routing in hypercubes using partial path set-up

A new technique is proposed for fault-tolerant routing in hypercubes, which needs to set up a partial path based on local safety information. Local safety information is utilized to guide fault-tolerant routing. Local safety is a centralized metric. A feasible path from the source to the destination may not be guaranteed at the source based on local safety information when the system contains a large number of faults, although a feasible path is available. A partial path is set up for fault-tolerant routing, where the header flit is forwarded until a maximal safe subcube is found to contain the current node and the destination. Backtracking is adopted only for the header along the minimum paths or non-minimum feasible paths, if necessary, in order to set up a partial feasible path. Extensive simulation results have shown that the partial path set-up scheme is quite useful for fault-tolerant routing, while the extra cost caused by path set-up is trivial.