We present adaptive network QoS (Quality of Service) technology that provides ongoing, end-to-end assurance that critical traffic belonging to admitted flows has bounded queuing loss, delay, and jitter. Our technology uses a Bandwidth Broker to provide admission control, and leverages Differentiated Services and Class of Service functionality of high-end routers and switches for enforcement. The technology employs an integrated QoS treatment across a hybrid layer-2/layer-3 network and adapts to changes in mission requirements, work load and configurations; it uses discovery algorithms in these layers to maintain a current view of resource availability. Under the DARPA ARMS (Adaptive and Reflective Middleware Systems) program, our technology is being developed, integrated and validated in a CORBA-based multi-layer resource management framework.