<span lang="en">This paper deals with the management of QoS as perceived by end users in corporate networks. First, we overview some previous results achieved by the research group in the field of estimating and managing the QoS. In this work we accomplished some validation tasks by means of simulation. Going on with the analysis of applicability of the general model to real-world, we propose here to analyze a network scenario that includes an MPLS IP VPN. In this scenario we can take into account all the agents involved in the provision of Internet services and moreover we can carry out a management of QoS in the network.</span>