MULTICOORDINATED ROUNDS Sample Clauses

MULTICOORDINATED ROUNDS. As the name suggests, multicoordinated rounds have multiple coordinators to which the proposers send their proposals in parallel. Similarly to what happens in single coordinated rounds, coordinators in a multicoordinated round forward the proposals from proposers to the ac- ceptors. Acceptors, however, only take into consideration proposals forwarded by a quorum of the round coordi- nators. This way, values may be accepted even if some coordinators crash, as long as a full quorum is alive. By requiring these coordinator quorums to intersect, the pro- tocol ensures that no two different values will be consid- ered on the same round and, thus, no collision happens on the acceptors. Hence, acceptor quorums are only required to satisfy Assumption 1, being more resilient than in Fast Paxos. Collisions, however, may occur at the coordinators if different proposals are sent in parallel. These collisions are inherently less expensive than collisions on the accep- tors in that they can be handled without any stable storage access [7]. Many algorithms in the literature may be seen as in- stances of Fast Paxos, in spite of several differences in their actual specifications. As an example, consider xxx- xxxxxxxx in the assumed failure model: some algorithms, were specified for the crash-stop model [12, 36, 20, 19, 15], some for the crash-recovery [23, 1, 18, 24], and some for the byzantine [10, 28, 40, 29]. Therefore, by present- ing multicoordination as an extension to Fast Paxos we make it simpler to derive multicoordinated modes to the other protocols. We do so in the next section by reviewing a multicoordinated consensus protocol [8].