The book, you are reading, deals with VoIP call and measurement of its quality in a certain given conditions. In the following pages the discussion will be about the basics of network protocols such as TCP, UPD, IP, and SIP. After that a brief introduction to QoS − measuring voice quality - for instance MOS and E-Model, and the importance of implementing QoS for VoIP. QoS parameters used in this project will be called "mechanisms", such as Best effort service, Integrated and Differentiated services. Based on these fundamentals I proposed a design of laboratory for quality of service measurement. The laboratory will be aimed at testing the quality of codecs with regard to bandwidth, jitter, delay and packet loss.