The future distributed systems will be very heterogeneous. They will consist of end computing systems with widely varying capabilities, interconnected by networks which offer very different services. Delivering data with a guaranteed level of service is a real problem that requires both support at the network level (integrated services networks) and a QoS (Quality of Service) management environment. This paper describes a simple and flexible approach to QoS management. This approach is based on resource reservation (by the way of traffic control) and application dynamic adaptation. It aimsattemps to provide a simple ans efficient solution to the best possible quality of transmission considering the level of resource reserved and the current network load. Our approach is compared to other classic QoS architectures. It is analysed, and evaluated with an experimental implementation in the Internet environment.