Congestion avoidance strategies in broadband packet networks

The authors examine the networking environment of the future, pose the technical questions that need to be addressed to provide service assurance, and propose a set of strategies for congestion avoidance. Congestion avoidance is recommended instead of congestion control, which has very limited value in a high-speed network, where the latency in detecting congestion and reacting to it may make the control ineffective. The proposed solution consists of enforcing rate-control at the network edges, bandwidth reservation for continuous bit oriented (CBO) traffic using a unique two-queue strategy, and a scheduler-based packet cross-connect system. Simulation results of a Q+ model of an access node are presented that quantify the performance of this solution and compare it to existing congestion control mechanisms. The results demonstrate that it is possible to meet the differing needs of traffic types needing datagram transport and those needing virtual-circuit transport by using an intelligent scheduling strategy and a meaningful packet transport protocol