Evaluation of popular VoIP services

The dominance of multimedia applications has increased with the emergence of high speed data networks. Among the multimedia applications, VoIP has placed itself in a strong position. However, the market is dominated by a number of VoIP applications with different architectural and protocol layouts. Therefore, analysis and comparison is necessary to understand their behavior and to define the QoS of these applications. This paper analyzes various performance aspects, points out the observed weaknesses, strengths and user expectations of VoIP applications. We focus on analyzing the application performance using holistic manner. Our focus is mainly concentrated on three widely used VoIP applications: Skype, GTalk, and Gizmo. Our analysis observed that, each the application has good performance figure under some criteria. However, no application has shown good performance under all criteria. In addition, current VoIP applications lack interconnection, inter-operability, flexibility, and integration with other services.