Cutset Manipulations for Communication Network Reliability Estimation

The problem of calculating the reliability of a communication network of given topology is discussed. The definition of failure is generalized from simple disconnection to the event that terminal capacity falls below some threshold, and simple methods are developed for bounding the probability of such failures and for approximating the mean time between failures (MTBF). It is shown that the cumulative distribution function of terminal capacity is readily calculated, and that the dependence of network reliability on individual link reliability is substantially different when the generalized (and more realistic) definition of failure is used.