Approximation Algorithms for Multiconstrained Quality-of-Service Routing ∗ Meongchul Song Sartaj Sahni Computer & Information Science & Engineering University of Florida {msong, sahni}@cise.ufl.edu August 3, 2005 Abstract We propose six new heuristics to find a source-to-destination path that satisfies two or more additive constraints on edge weights. Five of these heuristics become ǫ-approximation algorithms when their parameters are appropriately set. The performance of our new heuris- tics is compared experimentally with that of two recently proposed heuristics for the same problem. Keywords: Quality of service routing, interval partitioning, approximation algorithm, heuristic. 1 Introduction In unicast quality-of-service (QoS) routing, we wish to find a path from a source vertex to a destination vertex of a network. This path must satisfy specified constraints. Typical constraints fall into one of two categories – link and path [1]. Link constraints limit the use of certain edges of the network in constructing a QoS route while path constraints apply to entire source- to-destination paths. Bandwidth is the most common example cited for a link constraint. The QoS path we seek may be required to provide a minimum bandwidth. To meet this requirement, each link (or edge) of the constructed source-to-destination route/path must provide this much bandwidth. The most commonly cited examples of path constraints are cost, delay and delay jitter. Although each edge or link has a cost/delay/delay-jitter associated with it, the QoS constraint * This research was supported, in part, by the National Science Foundation under grant ITR-0326155 1