Un sistema distribuido es un programa que ejecuta sobre un conjunto i» de ordenadores conectados por líneas de comunicación. Una característica importante de estos sistemas es que pueden tolerar fallos de alguno de los ordenadores y seguir cumpliendo la función que tenían encomendada, todo ello manteniendo un estado consistente.Esta tesis estudia la tolerancia a fallos hardware, usando técnicas software. En primer lugar, se presenta una clasificación original de los trabajos realizados hasta el presente. A continuación se estudia un modelo orientado a procesos que tolera fallos mediante replicación de procesos, presentando un conjunto original de protocolos basados en un consenso distribuido. Por último, se demuestra la utilidad del modelo, estudiando su aplicación a diversos ejemplos paradigmáticos en sistemas distribuidos.

Abstract-Reliable Broadcast (RB) is a basic abstraction in distributed systems, because it allows processes to communicate consistently and reliably to each other. It guarantees that all correct process reliable deliver the same set of messages. This abstraction has been extensively investigated in distributed systems where all processes have different identifiers, and the communication channels are reliable. However, more and more anonymous systems appear due to the motivation of privacy. It is significant to extend RB into anonymous system model where each process has no identifier. In another hand, the requirement of reliable communication channels is not always satisfied in real systems. Henee, this paper is aimed to study RB abstraction in anonymous distributed systems with fair lossy communication channels.In distributed systems, symmetry always mean that two systems should be considered symmetric if they behave identically, and two components of a system should be considered symmetric if they are indistinguishable. Henee, the anonymous distributed systems is symmetry. The design difficulty of RB algorithm lies in how to break the symmetry of the system. In this paper, we propose to use a random function to break it. Firstly, a non-quiescent RB algorithm tolerating an arbitrary number of crashed processes is given. Then, we introduce an anonymous perfect failure detector AP*. Finally, we propose an extended and quiescent RB algorithm using AP*.