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Understanding CHOKe: throughput and spatial characteristics

Tang, Ao and Wang, Jiantao and Low, Steven H. (2004) Understanding CHOKe: throughput and spatial characteristics. IEEE/ACM Transactions on Networking, 12 (4). pp. 694-707. ISSN 1063-6692. http://resolver.caltech.edu/CaltechAUTHORS:TANieeeacmtn04

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Abstract

A recently proposed active queue management, CHOKe, is stateless, simple to implement, yet surprisingly effective in protecting TCP from UDP flows. We present an equilibrium model of TCP/CHOKe. We prove that, provided the number of TCP flows is large, the UDP bandwidth share peaks at (e+1)/sup -1/=0.269 when UDP input rate is slightly larger than link capacity, and drops to zero as UDP input rate tends to infinity. We clarify the spatial characteristics of the leaky buffer under CHOKe that produce this throughput behavior. Specifically, we prove that, as UDP input rate increases, even though the total number of UDP packets in the queue increases, their spatial distribution becomes more and more concentrated near the tail of the queue, and drops rapidly to zero toward the head of the queue. In stark contrast to a nonleaky FIFO buffer where UDP bandwidth shares would approach 1 as its input rate increases without bound, under CHOKe, UDP simultaneously maintains a large number of packets in the queue and receives a vanishingly small bandwidth share, the mechanism through which CHOKe protects TCP flows.


Item Type:Article
Additional Information:© Copyright 2004 IEEE. Reprinted with permission. Manuscript received January 2, 2003; revised January 23, 2004; approved by IEEE/ACM TRANSACTIONS ON NETWORKING Editor B. Prabhakar. [Posted online: 2004-09-03] This work was supported by the National Science Foundation under Grants ANI-0113425 and ANI-0230967, by the Air Force Office of Scientific Research under Grant F49620-03-1-0119, by the Army Research Office under Grant DAAD19-02-1-0283, and by Cisco. Partial and preliminary results were presented at the IEEE INFOCOM, San Francisco, CA, April 2003, and the ACM Sigmetrics, San Diego, CA, June, 2003. The authors are grateful to R. Pan of Stanford University for sharing the codes and K.Wang of Caltech for useful discussions
Subject Keywords:Active queue management, bandwidth share, CHOKe, leaky buffer, spatial characteristics
Record Number:CaltechAUTHORS:TANieeeacmtn04
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:TANieeeacmtn04
Alternative URL:http://dx.doi.org/10.1109/TNET.2004.833162
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8585
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:21 Aug 2007
Last Modified:26 Dec 2012 09:40

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