Network Admission Control for Fault-Tolerant QoS Provisioning

Michael Menth, Stefan Kopf, Joachim Charzinski


In a connection oriented network layer, admission control (AC) is easily combined with connection state management at each network node. However, after a link or node failure, existing connections are dropped or reservations must be restored on new paths, which requires high signalling effort. In contrast, a connectionless network layer like IP does not deal with connection or resource management at the network nodes. After a failure, connectivity is easily restored by rerouting, affecting higher layer connections only via some packet drops. Thus, a resource management scheme for IP should allow rerouting to cope with failures without affecting reservation states. A network admission control (NAC) handles reservations only at dedicated locations, e.g. the borders of a network, not burdening individual routers with admission decisions or reservation states. The NAC architecture enables resilient resource reservation, maintaining reservations even after failures and intra-domain rerouting. In this paper, we investigate the efficiency of three different distributed budget management schemes with single and multi-path routing. We show how the admission decision can be designed to be tolerable against failure scenarios by admitting only the amount of traffic that can still be carried after a failure and the corresponding rerouting.


Internet; Resource Management; Admission Control; Resilience; Network Layer Resilience; Fast Rerouting; Network Admission Control