QoS protocol and algorithm join forces

In general, routing is subdivided into two functionalities: routing protocols that keep the network state information up to date and routing algorithms that compute paths based on the information provided by the routing protocols. An excessive overhead prevents the distribution of all resource changes across the network, leading to stale link-state information. Besides inaccurate information, researchers have also resorted to inexact algorithms, because the general QoS path selection problem is NP-hard. Researchers have strived to optimize on either the protocol or the algorithm, but have hardly investigated how the two can benefit from each other. In this paper we combine QoS protocol and algorithm. Our solution guarantees a tunable bounded error margin on the link-state information and provides an exact polynomial-time algorithm for the selection of (multi-constrained) paths