This permutation is getting by interchanging the important significant bit in address with smallest significant bit.
Ex. Xn-1, Xn-2, and X1.X0 = X0 Xn-2 ....... X1 Xn-1
An interconnection network stand on this permutation is the butterfly network. A butterfly network is called a blocking network and it does not permit an arbitrary connection of N inputs to N outputs without clash. The butterfly network is customized in Benz network. The Benz network is said to be non-blocking network and it is produced by joining two butterfly networks back to back, in such a way that data flows forward through one and in reverse through the other.