Clarifying Misconceptions About Arbitrum's Timeboost Proposal

Understanding Timeboost and Its Purpose

As the Arbitrum DAO discusses Timeboost, a new transaction ordering policy proposed for Arbitrum chains, several misconceptions have emerged. Timeboost aims to enhance transaction ordering without introducing new Maximum Extractable Value (MEV) issues. According to Offchain Labs, these misunderstandings need clarification to ensure accurate public perception.

Misconception #1: Arbitrum Uses Ethereum L1's Transaction Model

A prevalent misconception is that Arbitrum uses the same transaction ordering and block-building model as Ethereum L1, leading to similar MEV issues. In reality, Arbitrum employs a First-Come, First-Served (FCFS) model, sequencing transactions as they arrive. Unlike Ethereum L1, Arbitrum's continuous sequencing avoids the pitfalls associated with block-by-block processing.

Misconception #2: Timeboost Introduces New MEV Types

Contrary to some beliefs, Timeboost does not create new MEV types. Instead, it adjusts the existing MEV dynamics by allowing users to gain a slight advantage in transaction processing. This mechanism balances MEV capture without introducing harmful externalities. Notably, Timeboost does not facilitate transaction reordering that could enable sandwich attacks.

Misconception #3: Timeboost Grants Excessive Power

Another misconception is that winning a Timeboost auction grants the winner undue control over transaction ordering. However, Timeboost only provides a 200ms head start, not absolute priority. The express lane's value is determined by the auction bid, and it does not guarantee the first position in every block. The system ensures fair competition and prevents monopolistic control.

Misconception #4: Centralization Risks

There are concerns that Timeboost could be monopolized by centralized entities, harming the Arbitrum ecosystem. However, the auction-based system encourages open competition, requiring dominant players to consistently outbid others. The express lane's 200ms advantage is designed to attract rational actors without allowing them to maintain static control.

Misconception #5: Eliminating Spam and Capturing All MEV

Some believe Timeboost aims to capture all MEV and eliminate spam entirely. However, its primary goal is to allow chain owners to capture a significant share of MEV while reducing FCFS arbitrage spam. This approach ensures a high-quality user experience with fast block times and robust protection against harmful MEV.

Ultimately, Timeboost is an optional feature for Arbitrum chains. Should it be disabled, the network would seamlessly revert to the FCFS model, maintaining its current security and efficiency. Each chain can independently decide whether to adopt Timeboost, adhering to the principle of decentralized governance.