The issue of protecting a fiber communication system is of considerable concern mainly because of the fiber's capability of carrying a large amount of traffic. In this study, we are concerned with the role of topology in relation to the survivability and network cost. Studying three simple network topologies, the ring, hub and mesh topologies, the ring topology is found to have many advantages for high capacity communication systems. Combinations of the simple network topologies may be used to combine the advantages of each topology. A toroidal grid topology, which combines advantages of ring and mesh topologies, is described and evaluated. Analytic results shows that the toroidal grid achieves survivability with lower incremental costs compared to the ring topology. The analytical results are limited to simple geometric and uniform traffic models. A computer program is developed to analyze the performance of more realistic networks. The computer results show that the length of a network system is a major factor affecting the cost of the network. The idea of having a multiply interconnected ring system appears to be an attractive topology for long-distance applications. / Master of Science