The MDX (Multi-Dimensional X'bar): A class of networks for large scale multiprocessors

The recent advance of semiconductor technologies enable to produce a medium size of crossbar with reasonable cost. By making the best use of the high bandwidth of such crossbars, indirect networks including the base-m n-cube and HyperCross have been proposed and researched. In these networks, a node is connected other nodes through crossbars in multiple dimensions. Although these networks are practically used in commercial machines, almost no discussion on a class of networks including them has been done. In this paper, a network class called Multi-Dimensional X'bar (MDX) which includes the above two networks is defined. Several new networks in this class are proposed, and relationship between these networks and direct networks/multistage interconnection networks is discussed. Finally, routing methods for these new networks are proposed and the average distance is evaluated. Through the discussion and evaluation, the MDX supports higher bandwidth than the corresponding multistage interconnection network with smaller hardware than the corresponding direct network.