The increased need for Quality of Service (QoS) in today?s networks has concentrated a lot of research and implementation efforts. Particular interest exists for the exploitation of the DiffServ framework towards the provision of qualitative services in MANs and WANs worldwide. Although individual mechanisms have been widely investigated, not many references to studies combining all levels of priority and QoS provisioning exist. This work aims at presenting a thorough and unified approach to the dimensioning and provisioning of a high priority service for high-quality demanding traffic over a MAN/WAN environment. Our approach anticipates for bounds in specific quality metrics and is demonstrated by the experimental case-study of a high-priority service over a MAN topology.