Original｜Odaily
Author｜Azuma
The controversy surrounding Layer 3 has intensified in the past two days.
On the one hand, the related tokens of representative Layer 3 projects such as Degen Chain have experienced astonishing increases in the past few days - DEGEN itself has a weekly increase of up to 143%; after Aavegotchi chose to transform into a Base-based Layer 3, GHST also strongly refreshed its historical high. .
But on the other hand, the community’s doubts about Layer 3 are getting louder and louder. Vitalik personally came out today to express his opposition:“Layer 3 doesn’t magically increase throughput.”
Yesterday was April Fools Day, and many projects took this as their focus and made some jokes about Layer 4 and Layer 5 in a somewhat joking manner. For example, dYdX once joked that the new version will be built based on L4. This The joke was even treated as news by some media outlets.
Feasibility assumptions for Layer 3
So why is Layer 3 so questioned? Why is the matryoshka logic of “Rollup plus Rollup” not politically correct enough? Judging from the discussion in the community, the focus of doubts surrounding Layer 3 is mainly on whether Layer 3 really has expansion significance.
From the classic definition,Layer 2 is often defined as a network that relies on the Ethereum main network for settlement and is scalable; by analogy, Layer 3 is defined as a network that relies on Layer 2 for settlement and is more scalable.
In the Layer 2 environment, the so-called relying on Ethereum for settlement is technically implemented as: packaging and compressing a large amount of Layer 2 transaction data, and then synchronizing it to the Ethereum network, and through Calldate (early solution ) or Blob (current scheme) data space for storage.
Ideally, if the settlement logic of Layer 2 is feasible, then the logic of Layer 3 relying on Layer 2 for settlement seems to be true. Its technical implementation mechanism should be: packaging and compressing a large amount of Layer 3 transaction data. , and then synchronized to the Layer 2 network...
At this point, problems begin to arise.
Since Layer 2 itself is not responsible for confirming the finality of the network, but relies on Ethereum,In theory, the Layer 3 data should eventually be submitted to Ethereum, and Ethereum will have the final say.
For Layer 3 compressed data that has been submitted to Layer 2, there are two potential submission modes (continue compression or no longer compress), but unfortunately, no matter which mode has certain problems for the time being.
The double paradox of Layer 3 data submission
The first is the first potential submission mode,The compressed data is compressed again and submitted to the Ethereum main network together with other Layer 2 transaction data.
It sounds wonderful, but the reality is cruel - No.
Vitalik wrote an analysis article about Layer 3 in 2022 What kind of Layer 3 is meaningful?, the article explained why we cannot compress transaction data multiple times.
Rollup uses a series of compression schemes to reduce the amount of data stored in transactions. A simple transfer can be compressed from about 100 bytes to about 16 bytes, and an ERC 20 transfer on an EVM-compatible chain can be compressed from about 180 bytes to About 23 bytes, a ZK-SNARK transaction can be compressed from about 600 bytes to about 80 bytes. All the above cases can achieve about 8 times compression efficiency... However, because Rollup still needs to maintain data availability on the chain to ensure that all data is accessible and verifiable by users, such as independently calculating the status of Rollup, or in existing When the verification node is offline, it joins as a new verification node...Data can be compressed once, but cannot be compressed repeatedly, which usually means we could put the logic of the second compressor into the first, if possible, but it also means we could have achieved the same effect with just one compression. Therefore, putting another Rollup on top of a Rollup does not have a real capacity expansion solution.
Simply put, due to data availability considerations, there are certain limitations in compressing transaction data.
Under this premise,If we can achieve multiple compression of Layer 3 data by integrating the logic of the second compression into the first compression process, this means that we can also directly perform multiple compression on Layer 2 data, and then perform multiple compression on Layer 2 data. The same expansion effect can be achieved by layer 3, so why do we still need Layer 3?
The reason is that the compression algorithm essentially removes data redundancy to a certain extent, making the data more compact. But once these redundancies are removed, it becomes more difficult to compress the already compressed data again. , because there will only be less and less redundancy that can be removed. Therefore, data compression is not a process that can be repeated infinitely, and the returns of compression are diminishing.
Next we look at the second potential submission mode,That is, Layer 3 data is no longer compressed, but is submitted directly to the Ethereum main network together with other Layer 2 transactions.
This also feels a bit baffling, because overall,The main bottleneck currently limiting the expansion of the Ethereum ecosystem is not the lack of block space on Layer 2 (including Layer 3), but the limited data availability and carrying capacity of the main network.——The Blob storage space used to store Layer 2 data is still limited.
Monad co-founder Keone Hon previously posted that the current Blob capacity is about three 125 kb Blobs per block (12 seconds), which is 31.25 kb per second. Given that the number of transactions is about 100 Bytes (slightly higher than the number given by Vitalik), this means that the shared TPS of all Layer 2 is about 300.
Under this premise, all Layer 2 (including Layer 3) will be subject to the same upper limit of data availability. This also makes it impossible to complete the finality confirmation no matter how much block space is provided by Layer 2 plus Layer 3. Sometimes you have to line up one by one.
This is why Vitalik emphasized that Layer 3 will not magically improve the expansion of the Ethereum ecosystem.
Is Layer 3 pointless?
Based on the above analysis, it can be seen that due to limitations in compression efficiency and upper limit of data availability, the current Layer 3 cannot provide significant effects in general expansion. So does this mean that Layer 3 is purely a pseudo-concept and has no practical significance? The answer is not so absolute.
Starkware was featured in Hierarchical expansion, from L2 to L3》 outlines some potential development directions of Layer 3. For example, Layer 2 can operate as a general-purpose network, and Layer 3 can operate as a dedicated network by strengthening customization functions. Another example is that Layer 2 can focus on trustless expansion, and Layer 3 can focus on trustless expansion. Then you can focus on weak trust expansion, that is, by introducing certain external trust conditions to deal with more difficult issues such as data availability.
Finally, apply Vitalik in What kind of Layer 3 is meaningful?Let’s end with the original words in: “Putting another Rollup on top of a Rollup, especially when the two layers use the same technical mechanism, is obviously not feasible. However, if Layer 2 and Layer 3 have different designs And for different goals, such a three-layer expansion architecture is feasible.
