Ethereum founder Vitalik Buterin shares his vision for Layer 3 protocols.

While Ethereum-based layer-2 solutions are highly focused on the network, Ethereum founder Vitalik Buterin believes that layer 3s serve a very different purpose – providing “tailored functionality”.

Buterin shared his thoughts in a September 17 post, where he outlined three “visions” of what Layer 3 might be used for in the future.

The Ethereum co-founder said a third layer on the blockchain would only make sense if it gave a different function to layer 2s, which was mainly used to improve scalability through zero-knowledge (ZK) packet technology.

A three-layer architecture that involves layering the same scaling scheme on top of itself generally does not perform well. Scrolls on scrolls where the two scrolls use the same technology will definitely not.

But “a three-layer architecture with a second layer and a third layer for different purposes can work,” Buterin said.

One of the Layer 3 use cases will be what Buterin describes as “custom functionality” – referring to privacy-oriented applications that use ZK authentications to deliver privacy-preserving transactions to Layer 2.

Another use case is “custom scaling” for special applications that don’t want to use Ethereum Virtual Machine (EVM) computation.

Buterin also said that layer 3 “weakly-trusted” validium, can be used for measurement through ZK-proof technology. Buterin said this could be “an average server that runs legal authentication and hashes to a chain on a regular basis” for “enterprise blockchain” applications.

But Buterin added that it is still unclear whether the Layer-3 architecture will be more efficient than the current Layer-2 model when building custom applications on Ethereum.

Layer-2 Vs Layer-3 Network Architecture. Source: Star ware

Related: A beginner’s guide to understanding the layers of blockchain technology

“One possible argument for a three-layer model over a two-layer model is that the three-layer model allows the entire ecosystem to be contained in a single package, allowing cross-domain operations within the ecosystem to be performed much more cheaply. In the more expensive layer 1 without having to go through it,” Buterin said.

But because cross-chain transactions can easily and cheaply be made between two Layer-2s committed to the same chain, building Layer 3s may not necessarily improve network efficiency, Buterin said.

Buterin’s comments on Layer 3 usage issues come as StarkWare’s newly minted iterative proofs seem to have put an end to Ethereum’s scalability concerns.

Dylan Fox, product manager at Ethereum software company Consensus, recently told Cointelegraph that “with repeated rolls and proofs, we can theoretically provide unlimited scalability.

These proof-of-concepts have been thoroughly tested in production, with Starkware founder Eli-Ben Sasson recently telling Cointelegraph that his proof-of-concept uses up to 600,000 NFT coins per transaction on Immutable X, and 60 million transactions could soon be possible with “further engineering and tuning” on the cards.