Two-Terminal Reliability Analysis of Telecommunication Networks Based on Reduction Method

Introduction . Methods for assessing the reliability of communication networks require simple and effective calculation tools. Although reduction methods allow the analysis of complex systems to be simplified, their application is limited by certain conditions. Aim . To investigate a reduction method based on the sequential transformation of networks with serial and parallel connections into equivalent circuits. Bipolar connectivity that implies a path between two dedicated nodes is considered, in contrast to multipolar connectivity that evaluates connectivity between several critical nodes and all-pole connectivity that requires paths between all nodes of the network. Materials and methods . Purely sequential and purely parallel structures, as well as their combinations, are considered. For sequential systems, the probability of operability is defined as the product of the serviceability probabilities of the elements, for parallel systems – through the probability of failure of all components. Results . For mixed structures, a reduction algorithm for calculating their reliability using simplified formulas is proposed. The reduction procedure and the final formulas for calculating network reliability are directly derived from the rules for serial and parallel connections. A communication network was used as an example to confirm the method accuracy provided that the failures of the elements are independent. Conclusion . The demonstrated reduction method is effective for analyzing the reliability of communication networks with series-parallel structures. The accuracy of calculations depends significantly on the assumption of the independence of failures. The advantages of the method include its simplicity and clarity; however, the method is inapplicable in cases of gradual failures and the interdependence of elements. In addition, this method processes correctly only loaded redundancy; for systems with unloaded or lightweight redundancy, the method needs to be modified. Computational difficulties for large-size networks and the possibility of information loss about the criticality of elements is noted. This is related to the loss of data on the contribution of individual components to the overall reliability of the system in the process of simplification, which impedes the analysis of weak links. The results obtained can be used in the design and optimization of communication networks, as well as for assessing their operational reliability.