Briefing
The foundational problem in Layer 2 architecture is the reliance on centralized sequencers, which introduces single points of failure for liveness and censorship, creating a critical misalignment with decentralization principles. This research proposes “Based Sequencing,” a mechanism that delegates Layer 2 transaction ordering rights to the credibly neutral Layer 1 validator set via specialized, high-performance “Gateways.” The core breakthrough is the enforcement of this delegation using L1-backed staking and slashing conditions on both the Gateways and the delegating proposers. This new architecture enables synchronous composability across a multi-rollup ecosystem, fundamentally aligning L2 security and credible neutrality with the economic security of the base layer.
Context
Before this research, rollups achieved high user experience and throughput by relying on a single, centralized sequencer to issue low-latency preconfirmations. This design, while performant, created a single point of failure susceptible to liveness failures and transaction censorship. The prevailing theoretical limitation was the need for an “escape hatch” mechanism to bypass a faulty sequencer, which always resulted in a degraded user experience due to significant delays, forcing a direct trade-off between performance and decentralization.
Analysis
The core mechanism of Based Sequencing operates on a lookahead schedule that maps L1 slots to a rotating set of specialized Gateways , which are the entities responsible for L2 sequencing. L1 proposers, the most credibly neutral actors, opt in to become sequencers and delegate their sequencing rights to these Gateways. The Gateways sequence transactions and distribute them as signed Frags (block fragments) via a fast, leader-aware gossip network.
This pipelined block construction allows follower nodes to optimistically validate and issue preconfirmations to users within milliseconds, maintaining a high-performance user experience. Accountability is enforced through a registry contract on L1 → Gateways and their delegating proposers post collateral and are subject to slashing for faults such as renegade preconfirmations or missing assigned slots, thereby inheriting the L1’s economic security guarantees.
Parameters
- Execution Preconfirmations Latency → Few milliseconds. (The speed at which a user receives a guarantee of transaction inclusion from the sequencer.)
- Demonstrated Throughput → 300,000 transactions per second. (The maximum transaction processing speed achieved by pipelined sequencers.)
- Liveness Failure Recovery → Two L1 slots. (The maximum time required for the system to recover from a faulty Gateway by rotating to the next scheduled leader.)
Outlook
The Based Sequencing design provides a clear, incremental roadmap for all major rollups to transition from a centralized to a credibly neutral, economically secured model. This shift will unlock a new generation of applications by enabling seamless, synchronous composability across the entire Layer 2 ecosystem and with the Layer 1. The research opens new avenues for mechanism design, specifically in developing robust, on-chain mechanisms for preventing front-running by malicious leaders, and precisely attributing liveness faults between the delegating proposers and the Gateways in a fully permissionless environment.
Verdict
Based Sequencing redefines the Layer 2 security model by cryptoeconomically inheriting the credible neutrality and economic security of the Layer 1 validator set.
