[e2e] a new paper on Adaptive RED
floyd at aciri.org
Wed Aug 1 14:55:48 PDT 2001
Ramki Gummadi, Scott Shenker, and I have a new paper out on "Adaptive
RED: An Algorithm for Increasing the Robustness of RED's Active
Queue Management", available from:
The abstract is appended below. The validation test for Adaptive
RED in the NS simulator can be run with "./test-all-adaptive-red"
in the directory tcl/test.
The RED active queue management algorithm allows network operators
to simultaneously achieve high throughput and low average delay.
However, the resulting average queue length is quite sensitive to
the level of congestion and to the RED parameter settings, and is
therefore not predictable in advance. Delay being a major component
of the quality of service delivered to their customers, network
operators would naturally like to have a rough a priori
estimate of the average delays in their congested routers; to
achieve such predictable average delays with RED would require
constant tuning of the parameters to adjust to current traffic
Our goal in this paper is to solve this problem with minimal changes
to the overall RED algorithm. To do so, we revisit the Adaptive
RED proposal of Feng et al. from 1997 [FKSS97, FKSS99]. We make
several algorithmic modifications to this proposal, while leaving
the basic idea intact, and then evaluate its performance using
simulation. We find that this revised version of Adaptive RED,
which can be implemented as a simple extension within RED routers,
removes the sensitivity to parameters that affect RED's performance
and can reliably achieve a specified target average queue length
in a wide variety of traffic scenarios. Based on extensive
simulations, we believe that Adaptive RED is sufficiently robust
for deployment in routers.
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