Fault tolerance in the Block-Shift Network

The Block Shift Network (BSN) is a new topology for interconnection networks in multiprocessor systems. BSN is a class of networks defined by several parameters, and has a constant number of links/node for some given parameters. Many popular networks such as the hypercube, the shuffle-exchange, and the complete networks, are instances of the BSN for different parameters. Performance of BSN has been evaluated through analysis, simulation, and design of typical parallel algorithms on it. The results indicate that BSN surpasses the hypercube in several respects while retaining most of the hypercube advantages, especially when the traffic has the locality property. As the size & complexity of a system increase, however, the reliability aspects become equally important and should be included in the system-performance study. This paper discusses the reliability issue of BSN. Several reliability measures, including network connectivity, network diagnosability, and 2-terminal reliability, are obtained through analysis. This paper shows that the BSN not only surpasses the hypercube in performance as confirmed before, but also has comparable reliability to the hypercube under similar conditions. BSN is also very flexible in balancing its cost and performance. One can increase two parameters to enhance the performance and reliability of the BSN, while it is impossible to do so in the hypercube once its size is fixed. The BSN can be an effective interconnection network for future parallel computer systems. Future research includes more accurate reliability analysis for BSN, development of more efficient fault-tolerant routing algorithms, design and analysis of fault-tolerant broadcast algorithm and multicast algorithms, and comparisons with various augmented or modified hypercubes in terms of reliability and fault tolerance.