Fault-tolerant routing and multicasting in hypercubes using a partial path set-up

A new technique is proposed for fault-tolerant routing and multicasting in hypercubes by using a combination of a partial path set-up scheme and local safety information, which is a variant of the pipelined-circuit-switching (PCS). A partial path is set up for fault-tolerant routing, where the header flit is forwarded until a maximal safe subcube containing the current node and the destination is found. Similarly, a partial multicast tree is set-up for multicasting until feasible paths from the leaves of the partial multicast tree to the destinations have been guaranteed. 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 multicast tree or a partial feasible path. Extensive simulation results show that the partial path set-up scheme greatly outperforms the previous fault-tolerant routing and multicasting methods while the extra latency caused by path set-up is trivial.