As the duties and options afforded to block proposers in Ethereum expand, the possibilities of interaction with the Lido protocol are expanded as well. In order to support broader ecosystem efforts to explore advanced block proposal activities on Ethereum, such as preconfirmations, Node Operators using the Lido protocol have new opportunities to test proposer protocols and sidecars.
The following initiatives allow operators to experiment, contribute, and prepare for future integrations with Lido’s growing infrastructure.
Auxiliary Proposer Mechanisms (APMs) are frameworks, usually consisting of processes, protocols, and software, that enable enhanced functionality compared to the default block proposal process in Ethereum. These mechanisms aim to improve various aspects of block production, such as efficiency, user experience, and network robustness, even potentially cross-chain or cross-layer communication, without fundamentally altering Ethereum’s core consensus rules. By operating in tandem with Ethereum validator infrastructure, they enable innovations like block optimization, faster confirmations, and increased censorship resistance.
APMs can be thought of as a framework for understanding and reasoning about the various mechanisms available to block proposers to enhance default block proposal functionality. A mechanism may be implemented by various different protocols, which may be enabled by various different sidecars (i.e. the relationship is 1 : n : n, although there may even be cases where sidecar enables multiple protocols.)
A Mechanism is a distinct objective paired with a method designed to achieve that objective within the Ethereum block proposal process.
Mechanisms outline what the objective is and how it can be achieved, providing the conceptual framework for developing protocols and sidecars. They do not prescribe a single implementation but the principles that inform the design of supporting tools.
Protocols are structured specifications of specific block proposal (or proposal augmentation) mechanisms.
Protocols define the rules, configurations, and workflows for how a particular mechanism operates within Ethereum’s ecosystem.
They can be "in-protocol," "out-of-protocol," or a hybrid. Here, "protocol" refers specifically to interactions occurring within the Ethereum protocol, its sub-protocols and networks.
Protocols provide a standardized approach to deploying and using these mechanisms, making them accessible to node operators and developers.
Sidecars are services or software components designed to support the functionality of a Protocol, essentially an implementation of parts of the protocol to allow agents to interact with the protocol and other agents within it.
Block proposer sidecars operate alongside the validator to perform specific tasks, provide additional services, optimizations, or data integration without altering the core validator software.
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A well-known example of an Auxiliary Proposer Mechanism is Proposer-Builder Separation (PBS). In the default Ethereum configuration, block proposers build blocks locally based on their view of the mempool. PBS, however, separates the tasks of building and proposing blocks into two distinct roles:
(Note: Some PBS implementations allow builders to submit partial payloads, which are then completed by either an intermediary builder or the proposer.)
The most widely recognized implementation of PBS is MEV Boost. MEV Boost is both a Protocol and a Sidecar, which can be confusing.
Other implementations of sidecars for the MEV Boost Protocol include:
Additionally, most Consensus Layer clients now support direct interaction with the MEV Boost Protocol, though this is not considered a sidecar and offers more limited functionality compared to MEV Boost (the Sidecar).
Another example of PBS is EIP 7732, which proposes enshrined PBS: ****an in-protocol implementation of PBS. Unlike MEV Boost, EIP 7732 operates entirely within the Ethereum protocol and is incompatible with the MEV Boost Protocol.
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These APMs are typically tested on the Hoodi testnet to ensure stability, scalability and performance before they can be considered to be integrated into mainnet operations.
By participating, Node Operators gain early access to new features on Ethereum and contribute valuable feedback to optimize their infrastructure:
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DAO Contributors are currently supporting testing for Commit-Boost (PBS) and invite applicable Node Operators* to participate in this phase.
** Applicable Node Operators currently are limited to Curated Module operators using the Lido protocol*
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