A hierarchical multipath approach to QoS routing: performance and cost evaluation

Efforts to provide connection oriented service over the inherently best-effort Internet started almost right after its birth. Today, there exist a multitude of solutions that have been proposed but have never been implemented due to their impracticability. We propose a practical solution for fast, low cost, scalable, and yet accurate QoS routing. We propose to use hierarchical approaches to make the scheme practical and cost-effective. At the same time, we increase network utilization and decrease inaccuracy of stale information by the use of multiple paths. An extensive simulation of the various permutations of schemes over a large set of topologies and traffic conditions validate the proposed schemes and prove conclusively that hierarchical schemes with multiple path capabilities not only result in significantly lower overhead, but also give high levels of QoS performance. This paper presents the architecture of our schemes, the multiple path computation algorithm, and the simulation results validating our claims.