The Internet has shown tremendous growth and continuous evolution in order to accommodate multimedia services including both voice and video applications. In particular, Internet telephony, or voice over IP is one of the most promising services currently being deployed. The Voice over IP (VoIP) significantly reduces long distance telephone charges by transferring all the longdistance voice and data over Internet connection. Besides the potentially significant cost reduction, Internet telephony offers many new features and easier integration with widely accepted Web- based services. Since VoIP shares the Internet connection with other forms of traffic, it must compete with other applications for voice quality. There still exists a number
of barriers to the widespread deployment of Internet telephony. One of the key challenges in implementing VoIP is to design and build an IP-based network that meets stringent QOS requirements. In order to deliver the high QOS that users demand, VoIP system designers must tackle various parameters specific to Packet network.

This paper proposes an automated test strategy for system testing Operating Systems in complex heterogeneous hardware and software environment and presents a sample implementation of the same for system testing IBM AIX Operating System. In recent years, with the availability of heterogeneous of servers, storage systems and software; IT environments have become so complex that many problem resolution requires Complete understanding of the customer’s product mix, integration and usage. Often development teams will find it difficult to reproduce and debug a problem on their development or test machines as it happens in a real world scenario. In absence of a heterogeneous Test environment, the chances that a critical Operating System bug escapes to the customer are very high. However system testing an Operating System under heterogeneous environment involving third party hardware and software products is a daunting task. The system test strategy proposed in this paper attempts to address this problem of not testing Operating Systems in real world customer like heterogeneous environmentined by conformity of the released product with the uality requirements and the cost of the project.