Unbeatable consensus

Armando Castañeda*, Yannai A. Gonczarowski, Yoram Moses

*Corresponding author for this work

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


The unbeatability of a consensus protocol, introduced by Halpern, Moses andWaarts in [15], is a stronger notion of optimality than the accepted notion of early stopping protocols. Using a novel knowledgebased analysis, this paper derives the first practical unbeatable consensus protocols in the literature, for the standard synchronous message-passing modelwith crash failures.These protocols strictly dominate the best known protocols for uniform and for non-uniform consensus, in some case beating them by a large margin. The analysis provides a new understanding of the logical structure of consensus, and of the distinction between uniform and nonuniform consensus. Finally, the first (early stopping and) unbeatable protocol that treats decision values “fairly” is presented. All of these protocols have very concise descriptions, and are shown to be efficiently implementable.

Original languageEnglish
Title of host publicationDistributed Computing - 28th International Symposium, DISC 2014, Proceedings
EditorsFabian Kuhn
PublisherSpringer Verlag
Number of pages16
ISBN (Electronic)9783662451731
StatePublished - 2014
Externally publishedYes
Event28th International Symposium on Distributed Computing, DISC 2014 - Austin, United States
Duration: 12 Oct 201415 Oct 2014

Publication series

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


Conference28th International Symposium on Distributed Computing, DISC 2014
Country/TerritoryUnited States


  • Consensus
  • Knowledge
  • Optimality
  • Uniform consensus


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