116 страниц. 2014 год. LAP Lambert Academic Publishing In this study, Quality of Service (QoS) investigation of VoIP traffic was performed in a real time network besides other types of network traffic such as web, database and video. The purpose of this study is to investigate the performance of various implementations of the VoIP Codecs over an IPv6 LAN, when the frame count per packet is increased. Each Codec was configured with different frame counts per packet to observe the impact of these differences on the VoIP QoS, in terms of voice packet end-to-end delay, jitter, IPv6-packet traffic dropped and Mean Opinion Score (MOS) statistics.As our best knowledge,this study is the first work in this field.