International Journal of Engineering and Information Systems (IJEAIS)   Year: 2019 | Volume: 3 | Issue: 9 | Page No.: 9-14 Performance Evaluation of VoIPv6 Service for Wireless Network Using OPNET Software Abdulhameed N. Hameed, Ahmed J. Abdulqader Abstract: Due to increase in the number of Internet users and the expansion of the newly applied services on the Internet such as Internet of Things (IoT) technology, the Internet Protocol version four (IPv4) has been developed to support this development of the Internet. Internet Protocol version six (IPv6) supports these capabilities by increasing the number of addresses available to connect large number of users to the global network. Deploying Voice over Internet Protocol (VoIP) service through wireless networks is a challenge for many network engineers. In this work different voice codec (coder-decoder) technologies (G.711, G.723 and G.729) are tested using Optimized Network Engineering Tool (OPNET) environment and their results are compared based on MOS (Mean Opinion Score), voice end to end delay and jitter parameters to investigate the quality of voice over IPv6 based wireless topology. Simulation results suggest that G.711 codec can be adopted to offer a best voice quality approach for VoIPv6 through Wi-Fi networks.