Improved competitive performance bounds for CIOQ switches

Alex Kesselman, Kirill Kogan, Michael Segal

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

6 Scopus citations


Combined input and output queued (CIOQ) architectures with a moderate fabric speedup S > 1 have come to play a major role in the design of high performance switches. In this paper we study CIOQ switches with First-In-First-Out (FIFO) buffers providing Quality of Service (QoS) guarantees. The goal of the switch policy is to maximize the total value of packets sent out of the switch. We analyze the performance of a switch policy by means of competitive analysis, where a uniform performance guarantee is provided for all traffic patterns. Azar and Richter [8] proposed an algorithm β-PG (Preemptive Greedy with a preemption factor of β) that is 8-competitive for an arbitrary speedup value when β= 3. We improve upon their result by showing that this algorithm achieves a competitive ratio of 7.5 and 7.47 for β= 3 and β= 2.8, respectively. Basically, we demonstrate that β-PG is at most β2+2β/β-1 and at least β2-β+1/β-1-competitive.

Original languageEnglish
Title of host publicationAlgorithms - ESA 2008 - 16th Annual European Symposium, Proceedings
PublisherSpringer Verlag
Number of pages12
ISBN (Print)3540877436, 9783540877431
StatePublished - 1 Jan 2008
Event16th Annual European Symposium on Algorithms, ESA 2008 - Karlsruhe, Germany
Duration: 15 Sep 200817 Sep 2008

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume5193 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference16th Annual European Symposium on Algorithms, ESA 2008

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science (all)


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