“…Meanwhile, the 2-stage network 2X(m, n) = S(m, n) + X(n, m) preserves several classes of 'conditionally non-blocking' switches, including 'unimodal-circular non-blocking' switches [11,17] and 0-1 'sorters' [11]. Symmetrically the 2-stage network X2(n, m) = X(n, m) + S(m, n) also preserves several classes of conditionally non-blocking switches, including 'circular-unimodal non-blocking switches' [11], 'circular sorters' [11] and 'circular-unimodal distributors' [18]. A 2 n × 2 n 'banyan-type network' is an n-stage MIN such that every stage consist of 2 n−1 2 × 2 nodes and every network input is connectable to every network output.…”