Path delay fault testing of a class of circuit-switched multistage interconnection networks

In this paper we consider path delay fault testing of a class of isomorphic Multistage Interconnection Networks (MINs) with centralized control using as representative the nxn Omega network. We show that the number of paths is 3n(2)-2n and we give a method for testing those applying only 2(3n-2) pairs of test vectors. We also show that this is the least number of test vector pairs that are required for testing all paths of the MIN. We also give a path selection method such that: a) the number of selected paths, that is, the number of paths that must be tested, is a small percentage of all paths and the propagation delay along every other path can be calculated from the propagation delays along the selected paths, b) all the selected paths are tested by using 2(3log(2)n+1) test vector pairs. Both methods derive strong delay-verification test sets.