Congestion Policing Queues - A new approach to managing bandwidth sharing at bottlenecks

Abstract

Managing bandwidth sharing at bottlenecks is a challenge as old as packet switched networks. When equal senders compete for bandwidth of a bottleneck, it is desirable not only to enforce an instantaneous sharing of the scarce resource but also to prevent permanently active customers from suppressing less active customers. Moreover, it is desirable to incentivize shifting load to non-congested networks or times. Today there is no cheap, efficient and effective mechanism available to achieve these goals. It has been argued that policing based on congestion as perceived by the transport layer can achieve these goals. In this paper we present the concept of Congestion Policing Queues (CPQ), based on a very lightweight dequeuing and scheduling because all customers share one queue. CPQs can police congestion if deployed at bottlenecks relevant to the customers' traffic. We developed three base policers that differ in the level of integration with the Active Queue Management (AQM) of the shared queue. By simulations of three scenarios we evaluate the robustness of the achieved resource sharing and performance in partial deployments for multi-bottleneck situations.