Bussed interconnection networks from trees

Pin limitations are a fundamental obstacle in the construction of massively parallel computers. The paper introduces a class of d-dimensional bussed hypercubes that can perform simultaneous bidirectional communication across any dimension using d+1, rather than 2d, ports per node. Each network Q/sub d/(T) is based on a tree T, which specifies the 'shape' of the busses, and can perform d(d+1)/2 permutations pi /sub ij/(x)=x(+)c/sub ij/ via a simple global command. This construction is then generalized to any d permutations II=( pi /sub 1/,. . ., pi /sub d/) of any set of nodes X. Given any edge-labeled directed tree T, whose kth arc is associated with the permutation pi /sub k/, a bussed network N(II,T) is constructed that can-in one clock tick-perform any of the O(d/sup 2/) permutations arising from the paths in the tree T.<>