High-end networked applications such as distance visualization and advanced collaborative environments have demanding quality of service (QoS) requirements. Particular challenges include the need to address a variety of types of flows, application-level monitoring and control, and end-to-end QoS across networks and other devices. We describe a QoS architecture and implementation that together help to address these challenges. The Globus Architecture for Reservation and Allocation (GARA) supports QoS on a variety of resources, immediate and advance reservations, monitoring and control of reservations, and end-to-end network reservations. We will describe how GARA works and various experiments that we have done with GARA on our testbed.