Iterative switching networks

In the paper the construction of the so called iterative networks is studied. This class contains rearrangeable N-inputs M-outputs networks carrying m connections with roughly 2(N+M) log (NM/(N+M)) contacts, if m = min(N,M) and with roughly 2(N+M) log m contacts, if m < min(N,M); these results are the best obtainable by the methods used.