Selective service protection in overload: differentiated services or per-flow admission control?

Network providers are currently obliged to significantly overprovision their networks in order to ensure satisfactory levels of quality in case of overload. Selective service protection would largely remove this requirement since only a minority of users actually requires such stringent availability guarantees. The paper reports simulation and emulation experiments on two potential selective service protection mechanisms: differentiated services queue management and implicit admission control. Results confirm that while both afford adequate protection to premium traffic, admission control achieves greater network efficiency and higher quality for the majority of best effort flows.