Tuning RED for Web Traffic: RED Considered Harmful?

A talk given by Kevin Jeffay at Sprint Advanced Technologies, Burlingame, CA, in March 2000.

Abstract: The IETF is promoting deployment of RED in Internet routers as an instance of active queue management for congestion avoidance. While the effect of RED on network-centric measures of performance has been well-studied, its effect on application-level measures of performance has not.

This talk presents the results of a study of the effects of RED on the performance of Web requests, specifically, response time for HTTP request-response transactions. We have empirically evaluated RED across a range of control parameter settings and offered loads in a laboratory setting. Our results show that:

We conclude that for links dominated by web traffic, RED appears to provide no clear advantage over FIFO for end-user response times. Moreover, given the lack of engineering practice to guide the setting of RED parameter values, and an existence proof that "reasonable," RED parameters values can result in poorer performance than FIFO queuing, it is possible that widespread RED deployment may cause more harm than good.

Get the slides for this talk.

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