From the current results, after the gas fee on the Ethereum L1 mainnet has dropped to a 5-year low, many projects feel that deploying on L1 may not be impossible. Therefore, many people will ask, what core problems are L2 currently solving?

There is an old topic called the impossible triangle of blockchain. According to Vitalik's explanation, it means that you can only choose two out of the three: [Security], [Decentralization], and [Scalability].

Returning to the essence of technology, this is the problem that L2 should solve:

First, state summaries are placed on L1, maintained by the mainnet for [Security];

Second, efforts are made to keep [Decentralization] as much as possible in the sorter;

Finally, [Scalability] is cleverly achieved by L2 off-chain as much as possible.

Different L2 solutions have their own merits, with OP Rollups and ZK Rollups being well-known. Today, I want to discuss something different, such as Based-Rollup.

The Based L2 solution was also proposed by Vitalik at the beginning, and L2 projects like Taiko have been promoting the Based Rollup concept.

PS: Note, it is Based, which has nothing to do with Coinbase's Base; Base is also OP-based.

As we all know, in a standard OP-based L2 system, the sorter has a lot of power. It can decide whose transactions come first and whose come later; even without malicious intent, it can profit through MEV. This is why projects like Metis propose decentralized sorters.

Different L2s handle MEV differently: for example, Arb advocates fair treatment of MEV (strictly according to first-come, first-served), while OP is more encouraging, believing that MEV is a free market behavior and thus taxes MEV. However, regardless of the approach, L2 sorters hold significant status.

Thus, Based-Rollup chooses to take a knife to the sorter—its concept is to let ETH L1 do the sorting, thereby limiting the power of L2 sorters.

Quoting a diagram from @taikoxyz documentation:

You can see that it is a three-step process:

Step 1: L2 seekers package L2 transactions and send them to L2 block builders;

Step 2: L2 block builders construct blocks;

Step 3: L1 seekers include L2 blocks in the blocks they build on L1.

Here, L1 seekers and L2 builders can be the same person.

This is another clever idea of 'doing two jobs at once'. In fact, the device performance of L1 seekers has redundancy, and building an additional Taiko L2 block does not add any pressure.

An inappropriate analogy would be, if ETH and L2 are likened to the relationship between a province and a city, then the idea of Based Rollup is: let the mayor (L2 builder) also serve as the deputy governor (L1 searcher), thus actually utilizing L1's resources to protect L2's security.

Taiko has been around for a whole year from TGE to now, and Token Unlock will soon begin. Therefore, Taiko has also brewed a new idea over the past year, called Based Booster Rollup/BBR.

Booster Rollup can also serve as a mirror of L1, and that idea is also interesting. However, due to limited space, the analysis of Booster Rollup will be expanded in the next article.