This paper is the first of a two part study summarizing the results of a research program on the survivability analysis of command and control communication

systems. In the first part, we consider the formulation of realistic survivability models and criteria, determine the fundamental physical problems affecting survivability analysis, and determine suitable approaches to the survivability problem. The second part first discusses algorithms for deterministic analysis of C
3systems to identify bottlenecks and more vulnerable elements in network structure. The problems encountered in probabilistic survivability analysis and basic probabilistic analysis techniques are then discussed. Finally, an efficient, practical probabilistic survivability analysis procedure is given and an example of its use is presented.