ALGOREP: Concensus for Asynchronous Systems

Les slides du cours

Est-ce qu'on est capable de creer un consensus asynchrone ?

Oui on l'utilise tous les jours
Un papier theorique dit non mais si c'etait le cas Facebook et machin ne fonctionneraient pas
En tout cas c'est impossible dans un mode completement asynchrone

FLP

Abstract of the paper
The consensus problem involves an asynchronous system of
processes,some of which may be unreliable. The problem is for the reliable processes to agree on a binary value. In this paper, it is shown that every protocol for this problem has the possibility of nontermination, even with only one faulty process.

Impossibility result
No completely asynchronous consensus protocol can tolerate even a single unannounced process death.

Problem description

Configurations