The W-Network: A low-cost fault-tolerant multistage interconnection network for fine-grain multiprocessing

Large‐scale multiprocessors require an efficient interconnection network to achieve good performance. This network, like the rest of the system, should be fault‐tolerant (able to continue operating even when there are hardware failures). This paper presents the W‐Network, a low‐cost fault‐tolerant MIN which is well‐suited to a large multiprocessor running fine‐grain parallel programs. It tolerates all single faults without any increases in latency or decreases in band‐width following a fault, because it behaves just like the fault‐free network even when there is a single fault. It requires only one extra port per chip, which makes it practical for a VLSI implementation. In addition, extra ports can be added for replacing faulty processors with spares.