An edge router based protocol for fault tolerant handling of advance reservations

To provide quality of service guarantees, resource reservation schemes have to maintain reservation states at the nodes along the path of a flow. Advance reservation schemes have to maintain these states for a long period of time. The loss of reservation state caused by node failures, makes advance reservation schemes highly susceptible to node failures. In this paper, we argue that a domain-by-domain reservation approach is inherently more fault tolerant than the traditional hop-by-hop approach. We propose a novel domain-based protocol for handling advance reservations. It requires support only at the edge routers and no changes are required at the core routers. We describe various factors which determine whether a flow´s advance reservation is handled properly by a network in the event of router failures. We use simulations to show that our protocol is highly fault tolerant. Our protocol does not require any static partitioning of bandwidth between best effort flows and reserved flows and thus keeps network utilization high.