<span lang="en">This paper presents a comprehensive model intended to analyse quality of service in telecommunications services. Many works have been published in this area, both from a technical viewpoint as well as taking into consideration subjective concerns. However, these works have not resulted in a unique methodology to assess the experienced quality. While most of the studies consider the quality of service from biased perspectives, we try to analyse quality of service as a general gauge of final users' satisfaction. The proposed model allows us to estimate the quality experienced by end users, while offering detailed analysis regarding the different agents involved in the service provision. Once we overview the most significant elements of the model, an in-depth analytical study is detailed. Finally, we illustrate a practical study for HTTP service in order to validate the theoretical model.</span>