Comments on "Tolerance of double-loop computer networks to multimode failures" by H. Masuyama and T. Ichimori

H. Masuyama and T. Ichimori (see IEEE Trans. Comput., vol.38, no.5, p.738-41, 1989) quantitatively evaluated the ability of a class of double-loop networks called forward-loop-backward-hop (FLBH) networks to tolerate node failures. Their approach was based on the enumeration of all possible sets of failures. The authors prove that their results are incorrect and demonstrate that it is difficult to solve this problem using an approach based on the enumeration of failure sets, suggesting that other approaches may be preferable.<>