The ubiquitous technology, leading the stream of change in telecommunication market, makes VoIP a foundation technology to enter NGN era. With this trend in mind, VoIP providers try to satisfy customer needs and invest on R&D in order to survive in this emerging market. The critical issues to VoIP providers are two fold the first one is to find out the quality attributes of Internet telephony service; and the second one is to assess the impact they have on customer satisfaction, customer loyalty and customer performance. In this study, we attempt to empirically answer the above two issues employing SEM (structural equation modeling) and AHP (analytic hierarchy process), and suggest strategic guidelines for successful deployment of Internet telephony service.