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Performance Analysis and Modeling
Full Paper
Tuning RED for Web Traffic
Mikkel Christiansen (University of North Carolina at Chapel Hill)
Kevin Jeffay (University of North Carolina at Chapel Hill)
David Ott (University of North Carolina at Chapel Hill)
F. Donelson Smith (University of North Carolina at Chapel Hill)
The IRTF is promoting deployment of RED in Internet routers. We study the effects of RED on the performance of Web requests with a novel aspect of our work being a concentration on a user-centric measure of performance \%97 response time for HTTP request-response transactions. We empirically evaluate RED across a range of control parameter settings and offered loads. Our results show that:
(1) contrary to expectations, compared to a (properly configured) FIFO queue, RED has a minimal effect on HTTP response times for offered loads up to 90\% of link capacity, (2) response times at loads in this range are not substantially effected by RED control parameters, (3) between 90\% and 100\% load, RED can be carefully tuned to yield performance somewhat superior to FIFO, however, response times are quite sensitive to the actual RED parameter values selected, and (4) in such congested networks, RED parameters that provide the best link utilization produce poorer response times.
We conclude that for links dominated by web traffic, RED appears to provide no clear advantage over FIFO for end-user response times.