Eion Incorporation

DiffServ networks support three forwarding classes: EF, AF and BE. Scheduling algorithms based on priority queueing such as Cisco LLQ and MDRR seem to be a natural choice to provide EF service. The main problem with priority queueing is that, due to lack of service isolation, QoS to AF classes may not be guaranteed if EF traffic is bursty. As an alternative, Fair Queueing schedulers can provide service isolation and guarantee QoS to all classes by reserving certain bandwidth. However, over-provisioning required by EF service leads to low bandwidth utilization. In this paper, we propose a bandwidth-efficient scheduler to provide QoS guarantees to both EF and AF classes. Simulation results show that the proposed scheduler outperforms Cisco MDRR in guaranteeing QoS to AF classes and excels fair queueing schedulers in bandwidth utilization. 1