Host-Based Service Differentiation with Congestion Feedback

Abstract

This paper investigates the possibility to differentiate services by using endpoint traffic controls, while sharing a single best-effort network The starting point is a scheme based on a combination of probe-based admission control in the end-systems for streaming traffic and error correction to isolate different flows. There are inherent limitations in pure host-based control mechanisms and we therefore investigate the improvement that can be achieved when explicit congestion notification is used in routers. In particular we investigate the sensitivity to different active queue management mechanisms and parameter settings. Simulations show that a high ECN marking rate helps to differentiate between flows, but it is important to make sure that the chosen AQM works well for the chosen parameters. This study also shows that a main benefit of ECN is to enable the extension of the scheme to wireless environments