Survivability analysis of self-healing SONET rings

Previously, a parametric state reward Markov model (SRMM/p), has been developed for the survivability analysis of self-healing SONET mesh networks. In order to handle the inherently high complexity of mesh networks, the model uses some complexity-reduction approximations. Since a ring is a simplified version of a mesh from the topological point of view, the SRMM/p is equally applicable to self-healing SONET rings (SONET SHRs). The uniformity and the simplicity of the rings allows one to include more details of the failures in the model so that the analysis is more accurate. To that end, we propose a probability-tree based evaluation of the probability of various system states resulting from all possible combinations of node and link failures. The resulting improvements in the reliability analysis are illustrated using experiments.