Reliability and availability engineering for VoIP communications systems

With the communications system, the designer is concerned with the equipment reliability, by which is meant the probability that the equipment will perform satisfactorily for a given period of time under specified conditions. At the other end the user is concerned with the availability which is the capability of a system to perform its prescribed functions satisfactorily at any time. This paper attempts to evaluate algorithms and engineering methodologies for analyzing the reliability and availability of communications networks, with the assumption that failures are concurrently and dynamical and can occur on both, hardware (nodes, links) and software. The model presented is a combination between a stateless model (reliability block diagram - IP_RBD) and a state based model (Markov chains - IP_Markov). The case study demonstrates the applicability of the model for the design and support of a deployable IP communication network. Preliminary results of proposed model application are provided and recommendations for future research as well.