Abstract: It is well known that company's Intranets are growing into ubiquitous communications media for everything. As a consequence, network traffic is notoriously dynamic, and unpredictable. Unfortunately, local area networks were designed for scalability and robustness, not for sophisticated traffic monitoring. This paper introduces a performance measurement method based on widely used IP protocol elements, which allows measurement of network performance criteria to predict the voice transmission feasibility of a given local area network. The measurement does neither depend on special VoIP equipment, nor does it need network monitoring hardware. Rather it uses special payload samples to detect unloaded network conditions to receive reference values. These samples are followed by typical VoIP application payload to obtain real-world measurement conditions. The validation of our method was done within a local area network and showed convincing results.