Application layer network performance evaluation of VoIP traffic on a test-bed with IPv4 and IPv6 LAN infrastructure

Transmission of voice over packet-based protocol has recently gained momentum. To this effect, Voice over Internet Protocol (VoIP) implementations on current and future versions of the Internet Protocols networks is becoming a convenient and inexpensive technology. This is the technology that is replacing traditional public switched telephone networks (PSTN). However, like any other such technology, VoIP offers both opportunities and has limitations. VoIP requires real time communication, however IP networks, which are at the core of all VoIP infrastructure, is not designed for such real time applications. Delay, latency, compromised data throughput and unacceptable round trip times that are commonly experienced on IP networks all may lead to voice quality degradation. The actual operating system platform on which VoIP application is in operation, network topology and the choice of communication protocols are all critical in ensuring that the VoIP is of acceptable quality. In this paper, five Windows operating systems (desktop and server) are configured with the two versions of Internet Protocol (one at a time) and empirically evaluated for performance difference for VoIP network traffic. The experiments are conducted on a test-bed, and performance related metrics like throughput, round trip time and latency are measured with five VoIP Codec types. The results show that VoIP network performance depends not only on IP version and Codec type, but also on the choice of the operating system.