A FRAMEWORK FOR CHARACTERIZING DISASTER-BASED NETWORK SURVIVABILITY

This paper formulates a general framework that includes and extends th e existing definitions for network survivability. Based on this framew ork, network survivability is characterized by a survivability functio n rather than a single value survivability measure, and various quanti ties of interest can be derived from the function. Examples are the ex pected survivability, the worst-case survivability, the r-percentile s urvivability, and the probability of zero survivability. The survivabi lity function is especially useful for the study of large-scale disast ers. For illustration, we derive the survivability function in closed form for a simple ring network under link failures. We also discuss th e general procedure for finding survivability functions for complex ne tworks, and show that the survivability function reveals useful inform ation about a network. This framework provides a unified and practical approach to analyzing and designing highly survivable communications networks.