Understand the consensus on ethereum: is it really only to the next block?

The world of blockchain and cryptocurrency can be confused, especially when it comes to consensus. In this article, we will deepen the concept of consensus in the context of ethereum and explore if there is a real agreement between the nodes on the network or if it is only temporary until the next block.

What is consensus?

In a blockchain network, Consensus referers to the process by which the nodes agreed on the state of the Block Chain. This means that once a node verifies certain conditions, such as transaction validation and data consistency, transmits its findings to the network. Receiver nodes work together to update their copies of blockchain, ensuring that everyone has an identical copy of the current state.

Ethereum consensus mechanism

Ethereum uses the test of work (POW), a consensus algorithm developed by Vitalik Buterin. In Pow, Nodes Compete to Solve Complex Mathematical Puzzles, which requirement significant computational power. The first node to solve the puzzle wins the right to validate transactions and create new blocks.

The Stage: Two Competitive Blockchain Tips

Let’s Imagine Two Competitive Blockchain Tips, Each Starting From Block A As a Main Block. The two tips are:

  • Type 1: “Block B is the right state of things.”

  • Council 2: “Block C is the right state of Things.”

Both blocks begin in block a, and diverge in different branches, with both nodes according to their respective versions of reality.

The First Blocks

In the first blocks, we don’t know what advice is correct. The nodes are still working to verify the transactions and consistency of the data, but none of the nodes has yet reached a consensus. In fact, it is possible that a node is in a state in which it believes that block b or block c is valid, while another node thinks otherwise.

The following Block: A Point of Agreement

When we reach block D (say), both nodes have reached a point where they agree in the state of blockchain. They have verified all transactions and data consistency, and can now update their copies of blockchain to reflect this agreement.

However, at this point, another block is still possible to appear and challenge the current consensus. If this block was transmitted, the nodes would need to verify their validity before accepting it as part of the block chain.

The following blockages: Another Division

After block e (again, say), both nodes again reach a point where they agree in the state of blockchain. But now, there is another branch that diverges from your agreement. In this case, the following block is:

  • Type 1: “Block f is the right state of things.”

  • Council 2: “The G Block is the right state of Things.”

Again, both nodes have reached a point where they are agree in the state of blockchain. However, Now Another Block may appear and challenge this new consensus.

The following blockages: Another Division

After Block H (Again), We See a Greater Divergence:

  • Type 1: “Block I is the right state of Things.”

  • Council 2: “The J Block is the right state of Things.”

This process continues, with each node reaching an agreement on the state of blockchain in later blocks. However, Another Block May appears and challenge this new consensus.

Conclusion

In conclusion, although we have reached a point where both nodes agree in the state of blockchain (Block J), there is still no real consensus until the next block is transmitted. This is because each node has reached an agreement independently at different points over time, and can carry multiple blocks to converge.

This phenomenon is known as “Blockchain Fork”, where two or more competitive versions of reality diverge from one point.