The Performance of HTTP Traffic Under Random Early Detection Queue Management

Mikkel Christiansen, Ph.D. 2002

Department of Computer Science
Aalborg University
January, 2002

(This dissertation is based on research completed while a visiting scholar at the University of North carolina at Chapel Hill.)


In RFC (Request For Comments) 2309 [9] the active queuing mechanism RED has been purposed for widespread deployment on Internet routers. This thesis presents an empirical study of the active queuing mechanism RED where we focus on the question: How will RED e ect HTTP response times and can RED be tuned to optimize these?

The empirical study is conducted on a laboratory network in which we model a typical scenario in which a router operates and becomes a bottleneck. A realistic HTTP traffic load is provided by a set traffic generator programs. These simulate the behavior of browsing users using an empirical model of HTTP traffic that is both well-founded as well as being widely accepted and used. Response time performance is measured for each request made in the simulation of browsing users, thus providing a detailed insight on the performance experienced by the end-user.

The study consists of finding the optimal RED parameters under different offered loads. Where the offered load describes the average bandwidth utilization produced by the traffic generators on a network with no bandwidth constraints. To determine the impact of using RED we compare the response time performance with our choice of optimal RED parameters with the optimal performance of tail-drop queuing and the performance on the laboratory network without bandwidth constraints.

The results of the study can be summarized as follows:

In total, we conclude that for links carrying Web traffic, RED queue management appears to provide no clear advantage over tail-drop for end-to-end response times.

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Last revised Wed Aug 6 13:04:44 EDT 2003 by jeffay at