[cx01]

Did you even read the Paxos Commit paper? There is no single arbitrator. And what is 'unknown state' intended to mean? The system will obviously always be in a known state. It will just block as long as there is no network connectivity.

[cassandravoiton]

Yes, I did read it... "

In practice, it is not di±cult to construct an algorithm that, except dur- ing rare periods of network instability, selects a suitable unique leader among a majority of nonfaulty acceptors. Transient failure of the leader-selection algorithm is harmless, violating neither safety nor eventual progress. One algorithm for leader selection is presented by Aguilera et al. [1] "

" The algorithm satisfies Stability because once an RM receives a decision from a leader, it never changes its view of what value has been chosen "

Fundamentally, the idea is that the leader is the transactional arbitrator using the RM as the recorder of that transaction.