This Recommendation is a diagnostic reference for IP network quality of service monitoring, and primarily as a guide to assist regulators monitor the quality of service of internet that is provided by service providers (although subscribers and network service providers may also derive benefit). It highlights the necessity of monitoring the QoS of network services offered by internet service providers (ISPs), from the diagnostic and regulatory points of view. The Recommendation also addresses quality of service evaluation scenarios, sampling methodology and testing tools for regulators. Finally, this Recommendation gives a guidance to regulators about minimum QoS parameters for evaluating the quality of internet services.