Democratizing the Parliament (extended Abstract)

This paper presents a replication algorithm that implements a highly-available, non-deterministic state machine. Our algorithm generalizes the Paxos parliament algorithm of Lamport to cope with non-deterministic computations, while preserving its nice resilience and e ciency properties. The algorithm is surprisingly simple, thanks to the use of two powerful underlying abstractions: weak consensus and weak leader election, together with a generic data structure: consensus bag. As a side-e ect of our work, we discuss some similarities and di erences between replicating deterministic and non-deterministic state machines. Indirectly, we revisit the traditional classi cation between state-machine replication and