Towards a standards-based Internet telephony system

Abstract An Internet telephony system is basically a computer-form of a conventional telephone to support real-time voice communication between two or more users who are connected to the Internet. A wide range of Internet telephony systems are currently marketed. However, most of these systems are developed using proprietary technology. Interoperability between systems from different vendors are not supported. In this paper, a standards-based approach is proposed to allow third-party Internet telephony systems to work together across standard-compliant operating systems and hardware platforms. An Internet telephony system, known as Internet Heterogeneous Phone (IHPhone), that uses directory servers to resolve dynamic IP addressing for establishing connections between users and the H.323 communications standard for voice communications, has been developed. This paper discusses in detail the design and implementation issues of the system. As part of performance evaluation, IHPhone has been compared with four existing Internet telephony systems using an evaluation framework that comprises a feature and functionality appraisal together with a set of qualitative and quantitative tests.