Design and implementation of scalable edge-based admission control

While the integrated services (IntServ) solution to Internet QoS can achiev e a strong service model that guarantees flow throughputs and loss rates, i t places excessive burdens on high-speed core routers to signal, schedule, and manage state for individual flows, Alternatively, the differentiated se rvices solution achieves scalability via aggregate control, yet cannot ensu re a particular QoS to individual flows. To simultaneously achieve scalabil ity and a strong service model, we have designed and implemented a novel ar chitecture and admission control algorithm termed egress admission control. In our approach, the available service on a network path is passively moni tored, and admission control is performed only at egress nodes, incorporati ng the effects of cross traffic with implicit measurements rather than with explicit signaling. In this paper, we describe our implementation of the s cheme on a network of prototype routers enhanced with ingress-egress path m onitoring and edge admission control. We report the results of testbed expe riments and demonstrate the feasibility of an edge-based architecture for p roviding IntServ-like services in a scalable way. (C) 2001 Elsevier Science B.V. All rights reserved.