Performance Evaluation 59 (2005) 337–366 Routing and rate allocation in rate-based multi-class networks  Aniruddha Diwan a, ∗ , Joy Kuri b a Motorola India Electronics Pvt. Ltd., “The Senate”, Ulsoor Road, Bangalore 560042, India b Centre for Electronics Design and Technology, Indian Institute of Science, Bangalore 560012, India Received 6 December 2003; received in revised form 23 August 2004 Available online 8 October 2004 Abstract In this paper, we investigate the performance of routing and rate allocation (RRA) algorithms in rate-based multi-class networks. On the arrival of a connection request, an RRA algorithm selects a route for the connection and allocates an appropriate rate on the route; failing this, it blocks the connection request. We measure the performance of an RRA algorithm in terms of its minimum weighted carried traffic. This performance criterion encompasses two widely used performance criteria, namely, weighted carried traffic and minimum carried traffic. We derive an upper bound on the minimum weighted carried traffic of any RRA algorithm. The bound can be computed by solving a linear program. Moreover, we show that the bound is achieved asymptotically, when the offered load and the link capacities are large, by a Partitioning RRA algorithm. Therefore the bound can be used as a performance benchmark for any RRA algorithm. We observe that the proposed Partitioning RRA algorithm, though asymptotically optimal, performs poorly at very low loads. We investigate the cause of this undesirable behaviour and obtain two improved asymptotically optimal RRA algorithms. © 2004 Elsevier B.V. All rights reserved. Keywords: Routing; Rate allocation; Multi-class networks 1. Introduction and overview In this paper we consider the QoS routing problem in the context of a rate-based multi-class network. In this model, a connection request belongs to one of several pre-specified classes. Each class has an  Parts of this work appeared in Proceedings of IEEE GLOBECOM 2002 and Proceedings of NCC 2003. ∗ Corresponding author. E-mail addresses: aniruddha@motorola.com (A. Diwan); kuri@cedt.iisc.ernet.in (J. Kuri) 0166-5316/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.peva.2004.08.005