In evaluating the performance of a communication network with unreliable components, researchers have traditionally approached the problem by enumerating all possible states of the system. Since the number of states of a communication network withnfailure-prone components is 2nthese methods are restricted to small systems. We present a new solution technique that is not doomed by the "statespace explosion" problem. Instead of enumerating all possible fail states, we consider only the most probable states. Since the network operates in these states most of the time, we can get upper and lower bounds and, hence, a good approximation of the network performance without having to analyze all possible states. We illustrate our solution technique by analyzing network reliability, the expected number of communicating pairs, and network average delay for some particular networks.