Blockchains are normally known as both a Layer-1 or Layer-2 resolution. Layer-1s are the bottom layer of an ecosystem comparable to Ethereum, Cardano, or Solana. Layer-2 options are anchored to Layer-1 blockchains and supply scalability.
Layer-3s may exist; nonetheless, you can not stack one other layer on high of Layer 2 so as to add much more scalability, Ethereum founder Vitalik Buterin wrote in a weblog put up on Sept. 17.
There are a number of challenges with stacking two equally designed layers on high of one another, Buterin wrote. For example, limits to information availability and reliance on Layer-1 bandwidth for emergency withdrawals can hinder the stacking of two layers.
Buterin mentioned that rollups on high of rollups couldn’t present greater scalability than Layer-2 options. Rollups compress the quantity of information a transaction must retailer on the Layer-1 blockchain to make sure the transaction will be accessed and verified.
Within the case of a easy token switch, the information is decreased from 100 to 16 bytes. For ZK-SNARK transactions that protect privateness, transaction information is compressed from 600 bytes to 80 bytes, Buterin mentioned.
However information can solely be compressed as soon as, Buterin wrote. If additional compression is feasible, the logic of the second compressor will be built-in into the primary in order that the information will be compressed simply as soon as with the identical outcomes. This is the reason rollups on high of rollups can not “present giant beneficial properties in scalability,” he wrote.
Three visions of L3 use-cases
StarkWare, which operates StarkNet, a ZK-rollup that serves as a Layer-2 Ethereum scaling resolution, laid out three totally different visions of how Layer-3s could possibly be used. Buterin considers all three visions as “basically affordable.”
Within the first state of affairs, Layer-3s can be utilized for personalized features comparable to privateness. The goal wouldn’t be to supply extra scalability in such a case. The Layer-2 would offer scalability to purposes, and a Layer-3 would serve the personalized performance wanted for various use instances.
Within the second imaginative and prescient, the Layer-2 gives general-purpose scaling, and the Layer-3 gives personalized scaling via specialised purposes. The Layer-3 would compute information via means apart from the EVM or rollups, whose information compression is optimized in line with particular information codecs.
Within the third imaginative and prescient, Layer-3s can present weakly-trusted scaling via Validiums, which use SNARKs to confirm computation. Knowledge availability, right here, is the accountability of a trusted third get together. Buterin mentioned that though Validiums supply a decrease safety grade than rollups, they’re “extremely underrated” and “vastly cheaper.”
Layer-3s can repair affirmation time vs mounted value tradeoffs of rollups
Whereas rollup transactions are low cost, rollups should pay a excessive mounted value each time they submit a batch of transactions to a Layer-1. For optimistic rollups that run on high of Layer-1s, the mounted value will be as excessive as 21,000-Layer-1-gas per batch, whereas for ZK rollups, the price can go as much as 400,000-gas per batch, in line with Buterin.
If rollups wait longer to submit extra transactions in a single batch to decrease the price, it will increase batch intervals. Because of this customers have to attend a really lengthy to get a affirmation of their transactions.
For a ZK rollup with a processing energy of 5tps to submit a batch of transactions in each Ethereum block (each 12 seconds), fuel per transaction would attain 10,368. Nonetheless, if the batch interval elevated to 1 minute, the fuel per transaction reduces to 2,368.
Within the case of a ZK rollup inside a ZK rollup, the fuel per transaction comes right down to 501 with batch intervals of 12 seconds. Therefore, Layer-3s can repair the time and value tradeoff for rollups.
What’s and isn’t a layer?
In line with Buterin, stacking the identical scaling options on high of one another doesn’t “work nicely,” which is why the rollup on high of rollup mannequin doesn’t make sense. Nonetheless, he argues {that a} three-layer construction the place the second and third layers are assigned totally different functions and features can work.
Nonetheless, there may be an unsolved semantic debate over what will be thought of as a layer and what can not, Buterin mentioned. He supplied his personal definition of what properties represent a Layer-2:
- “Their function is to extend scalability
- They comply with the “blockchain inside a blockchain” sample: they’ve their very own mechanism for processing transactions and their very own inside state
- They inherit the total safety of the Ethereum chain”
By B uterin’s definition, optimistic and ZK rollups are Layer-2s, however validiums, proof aggregations schemes, on-chain privateness techniques, and Solidity fall exterior the definition. Whereas a few of them will be known as Layer-3, not all of them ought to be, he wrote.
Buterin added that “it appears untimely to settle definitions whereas the structure of the multi-rollup ecosystem is way from set in stone” and many of the Layer-3 discussions are nonetheless theoretical.
However because the Layer-2 scaling ecosystem matures, Buterin expects extra refined and easier Layer-3 constructions to play a bigger position.
