BFT and PBFT and BA consensus algorithm

Question

I've been digging into some of the most used consensus algorithms in permissioned blockchains and I got stuck.

I understood that BFT (Byzantine Fault Tolerance) is a property of some algorithms and pBFT is an algorithm itself. Is that right?

This rule that 2/3 of the nodes in the network are enough to reach consensus, is it for all BFT algorithms or just pBFT?

Also what is the difference between Byzantine Agreement and BFT?

If you could provide a reliable source of information, I'd be thankful.

Answer 1

I understood that BFT (Byzantine Fault Tolerance) is a property of some algorithms and pBFT is an algorithm itself. Is that right?

Yes.

This rule that 2/3 of the nodes in the network are enough to reach consensus, is it for all BFT algorithms or just pBFT?

Algorithms for Byzantine agreement can tolerate at most f failures in 3f+1 nodes, but they may not even be able to tolerate that many. The reasoning is that, if the Byzantine nodes stop participating, then n-f nodes have to be able to reach consensus, but if message delays temporarily hide f good nodes, then the remaining good nodes should be in the majority (so n-f >= 2f+1, and n >= 3f+1).

Also what is the difference between Byzantine Agreement and BFT?

The former is a distributed computing problem, more often referred to as consensus. The latter is a property of a protocol.