LIB
LIB: last Irreversible Block, the last block that cannot be modified will be marked as LIB
How is the irreversible time of 163 seconds for the last EOS transaction calculated?
Prerequisite: There are 21 super nodes on the main network, each node produces 12 blocks in a row, and each block takes 0.5 seconds
Through the discussion between BM and V God, the node confirmation of DPOS is defined as two rounds. So the total confirmation time is: T = 2*(2/3) *21 *12 = 336block time
In theory, a block reaches the number of blocks required for final confirmation: T = 12*(14+13) + 1 = 325
The entire network requires 15 confirmations to reach a consensus. Everyone will confirm their own blocks by default, so each block requires 14 people's implicit confirm and (explicit) confirm. Since the 14th BP confirmed that the number of people has reached 15 including itself when the block was produced, it will issue an implicit confirm and an (explicit) confirm at the same time. Then, ideally, after a block is generated, it will not be able to obtain the consensus of the whole network and enter the LIB until the first block produced by the 28th BP afterwards. So there are the above calculations.
Official
Simplified formula: 325 = 27*12 +1
General: 最终确认块数 = ((2 * 2 * [BP数] / 3 ) - 1) * [BP每轮连续出块数] + 1
For example, a private network of 4 BPs: 37 = (2*2*3/3-1)*12+1