Authors: Vandana Gupta; S. Dharmaraja
Addresses: Department of Operational Research, Faculty of Mathematical Sciences, University of Delhi, Delhi 110007, India ' Department of Mathematics, Indian Institute of Technology Delhi, New Delhi 110016, India
Abstract: Nowadays Voice over IP (VoIP) has become an evolutionary technology in telecommunications. Because of the increasing dependencies of people on VoIP for voice communication, it is important to design a reliable and performance oriented VoIP system. In this paper a hierarchical model combining reliability and performance is proposed for a server based VoIP system on a wireless network. The top level reliability model consists of only the basic components of a VoIP system. Simultaneous failure of multiple components is taken into modelling consideration. Component redundancies and software rejuvenation are employed to achieve higher system reliability. Assuming exponential failure and repair times of the components, continuous time Markov chain is used to develop the top level reliability model. In addition, a lower level performance model is constructed to obtain the performance metrics of the system at each state of the top level reliability model. Numerical results are provided for the quantitative analysis of the proposed model.
Keywords: VoIP reliability; hierarchical modelling; Markov reward model; continuous time Markov chain; performance modelling; VoIP failure; multiple failures; component failures; Voice over IP; telecommunications; reliability modelling.
International Journal of Reliability and Safety, 2013 Vol.7 No.1, pp.58 - 74
Received: 12 Mar 2011
Accepted: 03 Oct 2011
Published online: 06 Aug 2013 *