Assessment of Internet voice transport with TCP

We investigate whether the current best-effort technology of Internet stands up to the high quality standards of real-time voice communication. More precisely, we assess VoIP quality within the context of transport protocol support and efficiency. Initially, we focus on TCP and UDP supportive role from the perspective of VoIP performance. Applying our metric for real-time performance, we reach the outcome that UDP is always not the protocol of choice for VoIP, since it occasionally exhibits inadequate performance. Beyond that, we evaluate a solution-framework based on TCP protocols, which favour realtime traffic. Based on our measurements, we assess the efficiency of the associated congestion control and congestion avoidance mechanisms in terms of VoIP performance. We also study the effect of packet size on protocol behaviour and VoIP quality. Furthermore, we investigate VoIP traffic friendliness, as well as potential tradeoffs between protocol performance and fairness. Copyright# 2006 John Wiley & Sons, Ltd.