Related Problems of PBFT algorithm

PBFT (99, 02 two papers)-from the beginning of the oral algorithm (the number of points) to the polynomial level

Request n>3f

Why

Personal simple Understanding: Note that the master node can be Byzantine, from the node to the (N,v,m) vote is based on the primary node (N,V,M). So the n is actually a F-Byzantine, and f a good node that may be affected by the Byzantine node (the good node may have confiscated all responses or received a false response from Byzantium, why not more than F?) Because more than f+1 can trigger a view change), only n-2f is left and must be greater than F (f possible decision from the Byzantine node)

Prepare phase guarantee is safety, to ensure that at least f+1 a good node received the same (N,V,M) vote, commit phase in fact, in order to protect liveness, to ensure that at least f+1 a good node for the same (N,V,M) has reached the confirmation of the submission, Commits mean execution, so when the view changes, these committed actions must be passed to the next view, or they will have to be rolled back (the rollback is complex). So ViewChange quorum is also 2f+1, to ensure that the f+1 a good node with the presence of at least 1 good nodes will correctly pass the previous view of all the submitted information, to ensure the liveness.

So quorum is 2f+1 because the F-answer is probably from the Byzantine node.

Related Problems of PBFT algorithm