A Solution for Evaluating the QoS of Voice over IP

Abstract

In this chapter, we present a solution for evaluating the Quality of Services (QoS) of Voice over Internet Protocol (VoIP). First, we present an introduction to the main concepts and mathematical background relating to QoS and Internet Protocol (IP) traffic nature, which subsequently are used in the measurements, analysis, and modeling of VoIP traffic. Secondly, we analyze network measurements and the result of the simulation in order to characterize the VoIP traffic nature. As results of this analysis, it is shown that VoIP jitter can be modeled by alpha-stable distributions and self-similar processes, with either Short or Long Range Dependence (i.e., SRD or LRD). Thirdly, we investigate the packet loss effects on the VoIP jitter, and present a methodology for simulating packet loss on VoIP jitter. Finally, we found an empirical relationship between the Hurst parameter (H) and the Packet Loss Rate (PLR); this relationship is based on voice traffic measurements and can be modeled by means of a power-law function with three fitted parameters.