60 likes | 165 Views
AF Testing Current Status and Perspectives. Octavio Medina Julio Orozco ENSTB / IRISA. TF-NGN meeting Southampton, UK 18/04/2002. Current Status. What has been done: Calibration of WRED Calibration of TCM for TCP What has been tested: BW distribution among UDP flows
E N D
AF TestingCurrent Status and Perspectives Octavio Medina Julio Orozco ENSTB / IRISA TF-NGN meeting Southampton, UK 18/04/2002
Current Status • What has been done: • Calibration of WRED • Calibration of TCM for TCP • What has been tested: • BW distribution among UDP flows • BW distribution among TCP aggregates • BW distribution TCP vs. UDP • What has been simulated • Individual TCP behavior • Aggregation • 2 level marking
Current Status • What’s missing
AF-Based Services • Until now, testing has focused in observing BW sharing among flows. • BW sharing under congestion not only depends on marking, but also on TCP behavior. • Difficult to imagine a large-scale service based on AF capacities. • AF offers priority-based packet drop in case of congestion. • Transport protocols don’t know how to take advantage of that. • A PHB for applications?
Perspectives • A service proposal may be imagined for CBR sources. • UDP multimedia flows • Shaped TCP aggregates ? • Tests & simulations for the CBR specific case can be specified. • Focus on Assured Bandwidth, forget BW sharing. • Concentrate on multi-layer multimedia needs?
Perspectives • Interest for an IP+ service has decreased • AF benefits are only seen under congestion. • Congestion not as frequent as before. • AF may be an alternative for LBE • Compare complexity to WRR. • Drawbacks related to delay. • Can AF improve ECN? • Any other possible use of AF?