Vitalik Buterns reveals Layer-3s to have “bigger role” as Layer-2 scaling ecosystem matures

Blockchains are commonly referred to as layer 1 or layer 2 solutions. Layer 1 is the base layer for ecosystems such as Ethereum, Cardano, and Solana. Layer 2 solutions are anchored to the Layer 1 blockchain and offer scalability.

Layer 3 can also exist. However, you can’t stack another layer on top of Layer 2 to add even more scalability, he wrote Ethereum founder Vitalik Buterin. blog post September 17th.

Buterin said stacking two similarly designed layers presents some challenges. For example, limitations on data availability and reliance on Layer 1 bandwidth for emergency withdrawals can prevent stacking two layers.

Buterin says that rollups on top of rollups don’t offer more scalability than layer 2 solutions. Rollup compresses the amount of data a transaction must store on the Layer 1 blockchain in order to be able to access and validate the transaction.

For a simple token transfer, the data is reduced from 100 bytes to 16 bytes. According to Buterin, for his privacy-preserving ZK-SNARK transactions, the transaction data will be compressed from 600 bytes to 80 bytes.

But data can only be compressed once, writes Buterin. If more compression is possible, the logic of the second compressor can be integrated into her first compressor so that the data can be compressed only once and still get the same result. This, he writes, is why rollups on top of rollups don’t “increase scalability significantly.”

Three visions of L3 use cases

StarkWare, which operates StarkNet, a ZK rollup that serves as a Layer 2 Ethereum scaling solution, has presented three different visions of how Layer 3 can be used. Buterin considers all three visions to be “fundamentally rational.”

In the first scenario, Layer 3 can be used for customized features such as privacy. In such cases, providing additional scalability is not the goal. Layer 2 provides scalability for your application, while Layer 3 provides customized functionality needed for different use cases.

In the second vision, layer 2 provides general purpose scaling and layer 3 provides customized scaling through specialized applications. Layer 3 computes data by means other than EVM or rollup, and its data compression is optimized according to the specific data format.

A third vision is that Layer 3 can provide unreliable scaling. baridiumValidate your calculations using SNARK. The availability of data here is the responsibility of a trusted third party. Buterin said Validium has a lower security grade than Rollup, but is “very underrated” and “very cheap.”

Layer 3 can fix rollup confirmation time vs. fixed cost tradeoff

Rollup transactions are cheap, but rollup has to pay a large fixed cost for each batch of transactions it sends to Layer 1. According to Buterin, for an optimistic rollup running on top of Layer 1, fixed costs can reach 21,000 Layer 1 gas per batch, while for ZK rollup, costs can go up to 400,000 per batch. It can become gas. .

To lower costs, the longer the rollup wait time to send more transactions in one batch, the longer the batch interval. This means that users have to wait a very long time to get confirmation of their transactions.

With a ZK rollup of 5tps of processing power and sending a batch of transactions per Ethereum block (every 12 seconds), the gas per transaction reaches 10,368. However, increasing the batch interval to 1 minute reduces the gas per transaction to 2,368.

For a ZK rollup within a ZK rollup, the gas per transaction goes down to 501 with a 12 second batch interval. Therefore, Layer 3 can fix the time/cost trade-off of rollup.

What are layers?

According to Buterin, it doesn’t make sense to roll up on top of the rollup model because the same scaling solution “won’t work” stacked on top of each other. However, he argues that a 3-layer structure, in which the purpose and function are divided between the 2nd and 3rd layers, is also acceptable.

But Buterin said there is an open semantic debate about what can and cannot be considered a layer. He provided his own definition of the properties that make up Layer 2.

• “Their aim is to increase scalability
• They follow a “blockchain within a blockchain” pattern. It has its own mechanism for handling transactions and its own internal state.
• They inherit the full security of the Ethereum chain. “

According to B uterin’s definition, Optimistic and ZK Rollup are Layer 2, while Validium, proof aggregation schemes, on-chain privacy systems, and Solidity are outside the scope of the definition. Some of them are sometimes called layer 3, he wrote, but not all should be called layer 3.

Buterin added, “The architecture of the multi-rollup ecosystem is far from finalized, and it seems premature to have a final definition,” adding that most of the Layer 3 discussion is still theoretical. Thing.

But as the Layer 2 scaling ecosystem matures, Buterin expects more sophisticated and simpler Layer 3 structures to play a bigger role.