PANews reported on July 1 that Ethereum co-founder Vitalik Buterin published an article titled "In-depth slot-and-epoch architecture to provide Ethereum users with a faster transaction confirmation time." The article states that although compared with five years ago, thanks to EIP-1559 and the merged stable block time, the transaction confirmation time on Ethereum L1 has been shortened to 5-20 seconds, which is comparable to the credit card payment experience, further reducing latency is still of great value, especially for those applications that require a few hundred milliseconds or even less latency.
In the paper, Buterin introduced the practical options explored by Ethereum to speed up transaction confirmation, focusing on single-slot finality in existing technologies. Currently, Ethereum's Gasper consensus mechanism adopts a slot-and-epoch architecture, but this mechanism is complex and the finality confirmation time is too long (12.8 minutes). SSF uses a mechanism similar to Tendermint to terminate the block before the next block is generated, while retaining the "inactive leakage" mechanism to ensure the stable operation and recovery ability of the chain. The main challenge of SSF is that it will bring a lot of load to the chain, but new proposals such as Orbit SSF are working to alleviate this problem. In addition, the paper also explores rollup pre-confirmation and pre-confirmation-based mechanisms. Ethereum is following a rollup-centric development route, designing L1 to support data availability and other functions, while the L2 protocol provides users with larger-scale services. However, L2 faces the challenge of providing faster confirmation speeds. To this end, a pre-confirmation mechanism came into being, which incentivizes professional proposers to provide pre-confirmation services in exchange for users' immediate guarantee that their transactions will be included in the next block.
Buterin emphasized that the slot-and-epoch architecture is obviously correct, but not all slot-and-epoch architectures are equal. He advocated a more comprehensive exploration of the design space, especially those options with stronger separation of concerns between the two mechanisms, in order to reduce transaction confirmation time and improve user experience. Buterin said that L2 can currently adopt three strategies: first, both technically and spiritually based on Ethereum, optimize itself to convey the technical characteristics and values of Ethereum; second, as a "server with blockchain Scaffold", by adding mechanisms such as validity proof and user rights protection, fully utilize the server efficiency while obtaining the benefits of the chain; third, adopt a compromise strategy to build a fast chain of one hundred nodes, with Ethereum providing interoperability and security. In the slot-and-epoch architecture, "epochs" represents Ethereum's SSF, while the meaning of "slots" varies in different situations. The key question is to what extent we can optimize the slot-and-epoch architecture based on Ethereum's native, and whether this will affect the application space of other types of pre-confirmation mechanisms. At present, there is still uncertainty about the complexity of block proposers and the design space of the slot-and-epoch architecture. Having more options will help better serve L1 and L2 users and simplify the work of L2 developers.