Abandoning the Layer 2 Definition: Vitalik's New Thinking on Ethereum Scaling Solutions
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Abandoning the Layer 2 Definition: Vitalik's New Thinking on Ethereum Scaling Solutions
Ethereum has always been the one that "defines" everything.
Navigating Web3 tides with focused insightsAuthor: Haotian
While everyone is debating Ethereum's "DA orthodoxy," @VitalikButerin and others are already discussing abandoning the definition of layer2 altogether.
Indeed, the term "layer2" easily maps directly to Rollup—and if it’s a Rollup, then questioning whether solutions without on-chain DA qualify as Ethereum layer2s makes sense.
Because Ethereum's scaling solutions include various approaches such as Plasma, Rollup, and Validium:
Plasma strictly requires data availability (DA) on the mainnet; Rollup is relatively more flexible—DA can be fully on-chain or hybrid. For example, most ZK-Rollups compress and back up data on-chain while performing computations off-chain, then use ZK proofs to synchronize state updates to the chain. Validium is even more flexible—DA is entirely off-chain, requiring only that a SNARK proof be submitted to the mainnet upon computation completion to ensure data consistency.
In fact, these different scaling solutions all represent trade-offs balancing security, decentralization, and scalability—the classic blockchain trilemma.
From a scaling perspective, each has its strengths and weaknesses. For instance, Plasma is suitable for secure layer-2 payment solutions, Validium fits better for highly scalable standalone app-chains, and Rollup became mainstream precisely because it strikes a middle ground—a balanced tradeoff.
That’s why Vitalik believes the current definition of layer2 is too narrow. He suggests categorizing layer2s into Strong L2 and Light L2 based on their emphasis on security or scalability. Only in this way can the layer2 ecosystem avoid being confined solely to Rollups, allowing other scaling approaches like Plasma and Validium to remain visible and viable.
So here comes the question: would it be acceptable to limit layer2 exclusively to Rollups? Vitalik offers his reasoning (commenting on four key points he raised):
1) Validium can be more secure than certain multisig-governed Rollups. This implies that if a scaling solution uses off-chain DA but submits results to the mainnet via SNARKs, the mainnet can verify and guarantee data integrity and correctness.
In terms of security, such an approach may actually surpass Rollup designs relying on multisig governance committees. Although Rollups are more popular, relying solely on multisigs for security is not truly trustworthy. This is a subtle critique urging Rollup projects to quickly address the vulnerability of depending on multisigs for security guarantees.
2) Properly implemented Rollups offer stronger security than Validium, because Rollups ensure on-chain data availability and integrity, enabling Ethereum validators to directly verify and enforce security—making it more direct and robust compared to Validium’s reliance on external security mechanisms.
Precisely due to this advantage, excessive focus on Rollups has made Validium appear illegitimate. Here, Vitalik seems to be emphasizing Validium’s legitimacy.
3) On-chain SNARKs + off-chain data can provide better security than pure on-chain fraud proofs + off-chain data. Because on-chain SNARKs at least guarantee the consistency and integrity of off-chain data. If there's a separate dataset off-chain and challenges rely solely on on-chain fraud proofs, in practical scenarios, the former is inherently safer than the latter.
This is essentially a criticism of schemes that store data off-chain but rely on on-chain fraud proofs. Fortunately, such designs are rare—most implementations using fraud proofs keep the data on-chain.
4) Finally, Vitalik emphasized that Rollups ≠ Layer2. He implicitly suggests that opportunities in directions like Plasma and Validium remain significant, and we must not confine the concept of layer2 solely to Rollups—if necessary, we should abandon the layer2 label altogether.
In my view, Vitalik’s move to decouple Rollup from the layer2 definition is wise. Because once the public equates layer2 exclusively with Rollup, Ethereum will be put on the defensive against third-party DA solutions like Celestia.
By broadening the conceptual framework now, developers can freely adopt third-party DA solutions like Celestia—if they submit SNARKs to Ethereum’s mainnet, it simply becomes part of Ethereum’s Validium-based scaling strategy. Moreover, developers can explore broader scaling avenues based on ZK+Plasma. No matter how the market evolves, Ethereum remains in control of the narrative and definitions.
It’s clear that Ethereum’s entire Lego-like architecture stands firmly on the visionary foresight provided by Vitalik!
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Haotian | CryptoInsight
