A fault-tolerant multistage combining network

In this paper, we propose a solution to both fault tolerance and hot-spot contention problems in multiprocessor systems with multistage interconnection networks. Combining networks are known to be effective in handling hot-spot traffic. However, the fault tolerance capability of unique-path combining network is insufficient and must be enhanced. Thus, we use the chaining scheme, which provides alternate routing paths by connecting intrastage switching elements with a chain, to enhance the fault tolerance capability of combining network. As a result, we propose a chained combining network. Because of the bidirectionality of combining networks, we also develop routing procedures for the chained combining network. With slight modifications, these routing procedures can also be used in other multipath fault-tolerant combining networks.