The “express channel” concept in hypermeshes and k-ary n-cubes

Low-dimensional k-ary n-cubes have been popular in recent multicomputers. However these networks suffer from high switching delays due to their high message distance. To overcome this problem, Dally (1990) has proposed express k-ary n-cubes with express channels, that allow non-local messages to partially bypass clusters of nodes within a dimension. The paper argues that hypergraph topologies, that provide total bypasses within a dimension, represent potential candidates as future high-performance networks. It presents a comparative study, of a regular hypergraph, referred to as the distributed crossbar switch hypermesh (DCSH), and the express k-ary n-cube, taking into account channel bandwidth constraints which apply in VLSI and multiple-chip technology. The study concludes that the DCSH´s total bypass strategy yields superior performance characteristics to the partial bypassing of its express cube counterpart