A summary of various Cross-L2 interoperability solutions

Author: HAOTIAN

Recently, @VitalikButerin said that Cross-L2 interoperability is no longer a problem. Although he did not specify the specific project, combined with the wonderful discussion in the comment area, I have summarized some solutions that can solve the interoperability of Cross-layer2, as follows:

1) Based-Rollup

In the Ethereum layer2 camp, there are some projects that pursue Compatible equivalence. By allowing layer2 and layer1 to share components as much as possible, they can achieve maximum compatibility with EVM, so that layer2 can directly hand over the sorter function to the main network.

Specifically, when retrieving Mempool transactions, the Proposer of the main network can use a special Route similar to MEV-Boost to capture the Rollup Batch transactions, and then directly complete the sorting and chaining on the main network. Representative Projects @taikoxyz

2) CrossChain-Rollup

The powerful ZK technology provides a possibility to establish a trustless mechanism for homogeneous/heterogeneous chains in complex environments, including interoperability between homogeneous chains such as EVM-Compatible, Cross-L2 belongs to this category. In addition, ZK technology can also connect the interoperability of complex non-smart contract-based chains such as EVM and Non-EVM.

Specifically, the ZK technology framework will become an underlying communication protocol, allowing homogeneous/heterogeneous chains to complete absolutely secure and reliable message transmission through Proof proof without checking the specific data of the other party and only verifying the Proof proof. ZK-Rollup is essentially the process of the off-chain layer2 calculating a large amount of data into Proofs proofs, and then letting the mainnet Rollup contract directly verify and finalize. Representative projects: @ProjectZKM  Entangled Rollup Network unified liquidity layer.

3) Intent-Rollup

Intent transactions have always been regarded as the key to the Crypto market embracing Mass Adoption. It can accommodate many related directions such as account abstraction, chain abstraction, AI Agent, Pre-Confirmation, etc. Intent transactions are essentially "abstracting" user needs to achieve programmable characteristics, and then using a decentralized solver platform to proxy and execute user needs to optimize the user-side transaction experience.

Intent will be the final destination of ideal transactions, which can lower the threshold for users to onboard into the Crypto market and attract incremental users to the industry. The intent track is not difficult to understand, but it is a huge challenge to program the user's vague and complex needs and then have them executed perfectly by the agent program, which requires a huge solver processing network. Representative Project: @dappOS_com

4) Layer2 Based-layer3

It is well known that the leading layer2 projects Arbitrum, Starknet, Optimism, etc. have successively launched layer3 application chain strategies. The layer3 application chain has customizable features, independent Tokenomics, and customizable Gas, but it relies on the basic components of layer2 to provide services, the most typical of which is interoperability.

The layer2 chain can provide a cross-application chain communication foundation for the layer3 application chain based on its own shared sequencer, shared prover, etc. Representative project: @arbitrum Orbit

5) Cosmos IBC Based -Rollup

The IBC communication framework of Cosmos provides a basic interoperability capability for all chains connected to the Cosmos Hub. If the capabilities of Cosmos IBC are focused on the Ethereum layer2 ecosystem, a layer2 interoperability layer based on the interoperability of Cosmos IBC will be realized.

This solution will directly retain the Cosmos SDK core code, while reducing development costs, while also being able to carry out targeted additional development for the Ethereum ecosystem, and then allow the universal interoperability of Cosmos to be perfectly implemented in the Ethereum ecosystem. Representative project: @Polymer_Labs

6) AVS Based -Rollup

Eigenlayer's middleware service protocol implements a capability that allows Ethereum mainnet Validators to commercialize their own consensus and deliver it to other Rollup layer2 or other homogeneous/heterogeneous chains.

This solution essentially allows Ethereum validators to repeatedly stake LST tokens, based on a set of reward and punishment economic mechanisms to constrain Validators to expand outside the chain to construct secure consensus for other chains. If layer2 uses AVS to construct consensus, it is equivalent to another economically driven Based-Rollup, and the mainnet components can participate in the cross-chain interactive process of layer2. Representative projects: @alt_layer

7) Modular-Rollups

When modularization reaches a certain level, the Rollup as a Service paradigm will drive the prosperity of the layer2 one-click chain issuance market. At that time, a layer2 network may share Celestia's DA data availability layer, Solana's VM or Ethereum EVM and other shared execution layers, as well as Ethereum as the shared settlement layer of these Rollups. To achieve absolute modular collaboration, cross-chain collaborative communication between different modules or different chains is a basic premise. Representative projects: @AvailProject

…Others

Note: Let me list only a few directions that I am familiar with, which may not be complete. There will be many projects that are working on the same direction at the same time and are differentiated. You can add them in the comment area. (All of them are aimed at eliminating centralized cross-chain bridges and CEX asset transfer stations)

I hope Vitalik can jump out and make such a voice more often, but please don't point to a certain project. The premise of To Vitalik's innovation is definitely not Vitalik's endorsement. Of course, there are some projects that will challenge the core position of Ethereum, but the future of Ethereum must break away from the Ethereum-centric thinking. Only by looking beyond Ethereum and looking at the Ethereum "ecosystem" can we see the whole picture, right?