Ethereum’s Rollup-Centric Roadmap: Challenges and Solutions

Ethereum’s rollup-centric roadmap has led to fragmented and isolated blockchains, which have led to a lack of value transfer between rollups. Shared sequencer mechanisms such as Espresso, Astria, and Radius have emerged as solutions. However, these solutions introduce new trust assumptions because these layers require their own set of security, Taiko says.

crossroads

Ethereum has prioritized decentralization from the beginning, which comes with certain constraints on the user experience. These constraints arise from the challenges of designing a decentralized distributed system, such as handling global state and sequential execution. In contrast, other layer 1 (L1) blockchains have sacrificed some decentralization for speed and low costs. This has resulted in higher hardware requirements for validators compared to Ethereum.

To address these issues, Ethereum adopted a rollup-centric roadmap four years ago, outsourcing execution to rollups to make the network more user-friendly until scalability upgrades like history expiration and statelessness could be implemented. This approach allowed Ethereum to achieve an average of 250 transactions per second (TPS) per day.

Shared sequencing layer

Current rollups use centralized sequencers, which pose the risk of censorship, liveness, and Miner Extractable Value (MEV) extraction. Shared sequencers provide a decentralized alternative, offering finality, decentralization, fast transactions, and cross-chain atomicity. However, shared sequencers introduce an honesty assumption, requiring at least half of the validators to be honest. If this assumption fails, the network may lose liveness, which can affect fast finality and transaction verification.

The shared sequencing layer redistributes MEV to all participating rollups by creating a marketplace where rollups can sell block space to the highest bidder. However, this system requires a large number of participating rollups to maintain the network effect. If a significant participant leaves, MEV distribution will be interrupted, affecting the overall value of the network.

Neutral Composition: Becoming a Foundation

Ethereum is considered the most reliable neutral layer for building decentralized applications. Rollups that use Ethereum as a sequencing layer are called “base rollups” and can be seamlessly combined with Ethereum and other base rollups. However, base rollups face issues such as 12-second block times, which limit transaction speed. Solutions such as base pre-confirmation and faster Ethereum block times are being explored to address these issues.

Base pre-check

Base pre-confirmation involves using a subset of Ethereum validators to provide fast transaction confirmations to Layer 2 (L2) users. This approach is currently being successfully tested on the Helder testnet and enables lightning-fast transactions in Taiko. However, base pre-confirmation does not inherit the full liveness and security of Ethereum, but instead relies on the trusted commitments of current Ethereum proposers.

Faster blocks

Faster block times on Ethereum will help with base rollups by reducing the time required to confirm transactions. A Single Slot Finality (SSF) consensus mechanism is being considered, which would allow each slot to be confirmed in a matter of seconds. However, SSF is vulnerable to a 33% inactivity leak, which poses a risk to network stability.

Despite the potential benefits of faster block times, Ethereum has chosen to prioritize decentralization and maintain support for solo home stakers. This decision is consistent with Ethereum’s long-term vision, but requires careful consideration and community consensus.

conclusion

As rollups become more popular, fragmentation and isolation present significant challenges. Shared sequencing layers provide solutions for fast finality and cross-chain composability, but introduce new trust assumptions. On the other hand, base rollups utilize Ethereum’s existing infrastructure, but face challenges with block times and revenue models.

Future solutions such as pre-verification and faster L1 block times aim to improve the user experience without compromising Ethereum’s alignment. The goal is to create a scalable, decentralized, and user-friendly ecosystem that stays true to Ethereum’s vision.

The choice of whether or not to base it is not simply a technical decision, but rather reflects the direction of the decentralized rollup framework.

Source: Tyco

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