ng on the edge between the perceived QoS and the assessed QoS. On one side, it includes the QoS perceived by the customer and QoS required by the customer, which belongs to the customer's side of ITU's QoS framework (the one with four viewpoints). On the other side, QoE also includes qualitative terms that refer to customer satisfaction from the provided service and additionally customer attraction to the service. Considering the performance model for QoS criteria, QoE is influenced by all seven defined criteria. For example, speed (e.g. bitrate in downlink and uplink) influences the latency as well as the resolution of the video (e.g. is it HD, full HD, or higher picture resolution), which directly impacts the customer's experience of that service (the video streaming service in this example). As with any other defined quality, QoE should also be assessed. The QoE assessment is performed by using subjective tests with metrics such as MOS, and that is in contrast to QoS which is assessed with objective metrics. Overall, it is clear that QoE must be assessed using subjective tests with metrics such as MOS, as standardized in ITU-T Rec. G.1011 [14]. However, it is also possible, and sometimes more convenient, to estimate QoE based on objective testing and then to apply associated quality estimation models. Using different quality estimation models, one can measure or calculate the objective parameters affecting QoE, with the aim of evaluating QoE. Why is such an approach - assessment of QoE as a subjective merit with measure- ment of objective parameters - needed? Because subjective tests require more resources and effort (e.g. they require human subjects), while objective measurement and auto- matic calculations using appropriate quality estimation models are generally faster and cheaper. 1.5.2 QoS and QoE Standards With the aim of defining and then assessing QoS and QoE, there are required stan- dards which can provide globally acceptable parameters that can be assessed and that are important to customers, servic