PDF-Impossibility of Distributed Consensus with One Faulty

FISCHER Yale University New Haven Connecticut NANCY A LYNCH Massachusetts Institute of Technology Cambridge Massachusetts AND MICHAEL S PATERSON University of Warwick Coventry England Abstract The consensus problem involves an asynchronous system of. Game Theory. Social Choice Theory. Jess Barak. Game Theory. Three basic elements of any game:. Set of players or participants. Moves or actions each player makes. Scores or payoffs that each player earns at the end. What are the advantages and disadvantages . CONSENSUS – decisions are not made unless everyone agrees.. Issues are debated and discussed until everyone agrees on a course of action. Consensus decision-making is relatively rare for government. In most democracies, decisions are made according to a majority vote. Because the representatives belong to different political parties, regions, and so forth, consensus in a democracy is difficult to achieve.. Jacob Beal. Social Concepts in Self-Adaptive and Self-Organising Systems. IEEE SASO. September, 2013. Asymmetry trades robustness for speed. Spanning Tree. Consensus. Laplacian. Consensus. O(diameter). Hao. Li. In English. People have different ideas. They reach agreement after discussion: consensus. Given consensus, one idea is chosen. In computer science. Distributed system – processes propose different values. Auxiliary Input or a Universal Simulator. Nir. . Bitansky. . Ran Canetti. Henry Cohn. Shafi. . Goldwasser. Yael . Tauman-Kalai. . Omer Paneth. Alon. Rosen. Program Obfuscation. Obfuscated program. Nir. . Bitansky. and Omer . Paneth. Program Obfuscation. Compute .  .  .  . Program Obfuscation.  .  . Program Obfuscation. Sign email . with . If . starts with “omer@bu.edu”.  .  .  . Ken Birman. Fall 2012. Consensus… a classic problem. Consensus abstraction underlies many distributed systems and protocols. N processes. They start execution with inputs.  {0,1}. Asynchronous, reliable network. to increasing support for climate action. John Cook. Global Change Institute, University of Queensland. 19 Sep 2013. “Science . is not a democracy. . It . is a dictatorship. . It . is evidence that does the dictating. Recommendations for Consensus Statement Development Pilot Project (Resolution 14.4). Issues Brought Forward. Consensus in the development process is unanimous minus two but consensus from Congress is unanimous. Therefore, if someone does not agree with the consensus statement during the development process, it can still be passed along to Congress where it will likely be voted down.. English III. What does that even mean?. And . is a useful little word for joining ideas, but when two or more independent clauses of unequal importance are joined by . and . or another coordinating conjunction, the result is . The processes of persuasion, compromise, consensus building and negotiation contribute to the resolution of conflicts and differences . Differences. Has anyone gotten into an argument recently?. What was it about?. Dennis Shasha (following Lynch, Fischer, Patterson). Failure Model. Processes can fail-stop (but that is all; no fail traitorous).. Communication is two-way.. Messages can be dropped or take an arbitrarily long time.. When you can’t agree to disagree. Consensus. Why do applications need consensus?. What does it mean to have consensus?. Consensus = consistency. Assumptions. Processes can choose values. Run at arbitrary speeds. Paxos Made Simple One-shot Paxos: solving consensus Multipaxos: Efficient state machine replication One-shot Paxos: solving consensus Multipaxos: Efficient state machine replication Consensus Get N nodes to agree on a value