Abstract.The s-t-network with highly reliable edges with repair and variable external load is considered. A fast simulation method is proposed, which allows evaluating the probability of functional failure when the real capacity of the network is less than the required capacity. It is proved that under some weak conditions the estimate has a bounded relative error as edges reliability increases. The numerical example illustrates the efficiency of the method.

Keywords: s-t-network, functional failure, minimal cutset, fast simulation method, variance of the estimate, relative standard deviation