Abstract: The Integrated services (Intserv) architecture provides the Internet the ability of delivering End-to-End QoS to applications over heterogeneous networks. Existing approaches for providing Intserv require routers to manage per flow states and perform per flow operations. Such a stateful network raises the scalability concerns when the network size or the number of flows is significantly large. The Differentiated Services (Diffserv) approach proposes a scalable means to deliver IP QoS based on aggregate traffic handling. In this paper, we present End-to-End QoS Guaranteed Services over Diffserv network. This is implemented by introducing an Sender-initiated resource reservation mechanism over Diffserv. This way we can simultaneously achieve scalability and better control on the services. We present a detailed experimental study of the End-to-End QoS behaviours. Our results demonstrate that it is very desirable to implement the reservation mechanism over Diffserv to achieve more flexible and efficient End-to-End guaranteed QoS.