Layer2 可以在 Layer1 基礎上，通過各種技術手段大大提高吞吐量和降低 gas fee，讓普通用戶也能輕鬆使用 dApp 和 DeFi 服務，享受到真正高速便宜的區塊鏈交易體驗。讓區塊鏈技術可以走向百萬用戶級的商業應用領域。
What is Layer2?
Layer2 refers to the second layer protocol built on the public blockchain (Layer1). The purpose is to expand the transaction capabilities and application scenarios of the blockchain. Currently, most common Layer2 are built on the basis of the Ethereum network. superior.
Layer2 builds a secondary protocol network outside the main chain, places most transactions and executions on Layer2, and then regularly submits the results in batches to Layer1 for verification through various mechanisms.
This can greatly improve the transaction speed of the blockchain and reduce transaction costs. At the same time, Layer2 also inherits the decentralization, security and privacy advantages of the public chain.
Why is Layer2 important?
Although Layer 1 public chains such as Ethereum provide decentralized and censorship-proof infrastructure, they have limitations in transaction speed and cost. Especially when DeFi, GameFi and NFT are popular in the bull market, the network will encounter congestion, and gas fees (network handling fees) will also soar to sky-high prices, making it unaffordable for many users who want to use dApps.
We all know that blockchain is supposed to be a cheaper and faster way to conduct transactions, which is its core value and attraction. But if each transaction costs hundreds of dollars in gas fees, what’s the difference with traditional payment tools like Visa, Paypal, wire transfers, etc.? In order to avoid the 1~3% handling fee, users have to bear higher blockchain transaction costs, which simply cannot attract Web2 users to use it.
And this is where Layer2 comes in handy!
Layer2 can greatly improve throughput and reduce gas fees (network handling fees) through various technical means based on Layer1. This solves the pain point of insufficient scalability of Layer 1, allowing ordinary users to easily use dApp and DeFi services and enjoy a truly high-speed and cheap blockchain transaction experience. Let cryptocurrencies move towards commercial applications with millions of users, instead of just staying in niche areas.
For public chain networks, Layer 2 can bring the following advantages:
Expand the transaction capabilities of the blockchain: Layer 1 is difficult to support large-scale commercial applications because the transaction speed is limited by the block time. Layer2 can greatly improve the transaction speed per second (TPS) and achieve high transaction throughput.
Reduce transaction costs: Operating on Layer 2 can avoid the high gas fees (network handling fees) of Layer 1, making blockchain applications affordable for more users.
Expanding functions and application scenarios: Layer 2 can introduce more functions, such as privacy protection, cross-chain operations, etc., to expand the application of blockchain.
Improve user experience: Layer2 transaction experience can be closer to traditional Web2 applications, allowing more non-technical users to use it easily.
Protect Layer1 security: Placing a large number of transaction processing on Layer2 can reduce the load on Layer1 and improve security.
How Layer2 works: Channels, sidechains, Validiums, rollup
Common Layer2 protocol technologies mainly include the following:
1. Channels (status channel, payment channel)
Channels are the earliest form of Layer2 technology. It allows two or more parties to conduct multiple transactions off-chain without broadcasting each transaction to the entire network. It avoids having to leave records on the Layer1 chain every time, reduces fees by reducing the number of transactions that need to be processed, and significantly improves the scalability of the blockchain.
For example, the Lightning Network runs on Layer 2 of the Bitcoin blockchain. Through the Lightning Network, users can quickly pay each other and settle many transactions at once without the need to transmit them on the main chain every time.
This can greatly improve the throughput of the Bitcoin blockchain and also reduce transaction costs and waiting times. The user experience is almost the same as a traditional payment app, but with the security and auditability of blockchain.
2. Sidechains Sidechains
The side chain operates using its own consensus mechanism and is a blockchain that operates independently but can communicate with the main chain. It provides a fast channel that allows assets to quickly circulate between the main chain and the side chain at a specific time.
However, since the side chain operates independently and is not protected by the main chain, it is responsible for maintaining security. This requires consuming additional computing power or resources, such as POS or POW consensus mechanisms.
Currently, the well-known side chain solutions in Ethereum are mainly xDai and Gnosis chains. These side chains all provide high-speed channels for Ethereum. Developers can utilize the free nodes of these sidechains to develop dApps.
While sidechains are not required to submit state data to the main chain, many sidechains still choose to do so to take advantage of the security of the larger, more decentralized chain.
3. Validiums
Validiums is similar to a side chain. It is an independently running blockchain but is closely connected to the main chain. Validiums mainly uses zero-knowledge proof rather than traditional proof of work or proof of equity mechanism.
Although Validiums uses zero-knowledge proof encryption technology, it differs from zk-Rollup in that the transaction data is not stored on the Layer1 main chain, so Validium can prove that the transaction is valid and valid without exposing the real transaction information. Comply with preset rules.
But like sidechains, Validium also has limitations. Because it does not rely on the security of the main chain, it needs to build its own consensus layer, which places higher requirements on developers. Smart contract support is also relatively limited.
Simply put, Validium is a technology between sidechains and Layer2 Rollup. It has a connecting bridge with the main chain and can interact with assets. But you need to ensure safety yourself.
Projects currently using the Validium Layer2 solution include StarkWare, Immutable X, ApeX, etc.
Rollups – Optimistic Rollup、zk – Rollup
Rollup is the most popular Layer 2 technology today. The basic concept is to package transaction data and submit it to Layer 1 in the form of Rollup. Mainly divided into two schools:
Optimistic Rollup
Optimistic Rollup is currently the most widely used Layer2 solution, represented by projects such as Arbitrum and Optimism. The advantage is that it is easy to develop and deploy, and can quickly attract applications. The disadvantage is that there is a certain risk of fraud, which needs to be prevented by relying on economic mechanisms.
zk-Rollup
zk-Rollup uses what are called zero-knowledge proofs (ZK-proofs) to verify the authenticity of transactions, which can be used to improve privacy on the blockchain as it allows sensitive information about the transaction to be verified without revealing sensitive information about the transaction. , to verify transactions. The disadvantage is that it is difficult to develop. Representative projects include zkSync, Polygon zkEVM, and Linea.
The emergence of zero-knowledge proof technology is likely to become a future adoption solution for enterprises because it can only display the information they want to convey to third parties (users) while transmitting sensitive data securely.
difference
Overall, ZK rollups can bring higher efficiency, but the biggest difference between Optimistic Rollup and ZK Rollup is that Optimistic is directly compatible with EVM, so anything possible on Layer1 is directly achievable on Layer2.
However, in order to solve the EVM compatibility problem of ZK rollups, zkEVM solutions gradually emerged. For information about zkEVM, please refer to "What is zkEVM? What projects and airdrops can be ambushed?"
What are the popular Layer2 projects and tokens?
According to the cryptocurrency data website L2BEAT, Arbitrum and OP Mainner are the Layer 2 projects with the largest locked positions on the market so far. The following will introduce you to the popular Layer 2 projects currently on the market one by one:
Optimism
Optimism is the earliest Optimistic Rollup project in the Ethereum ecosystem and also focuses on building an efficient EVM execution environment. Although it has an earlier development history, it has recently been undergoing accelerated upgrades and provides a set of easy-to-develop software tools called OP Stack.
OP Stack is mainly managed and maintained by Optimism Collective, which simplifies the process of creating Layer 2 blockchain and greatly reduces development costs. Developers can use the OP Stack toolkit to assemble a customized Layer 2 network according to their own needs and scenarios, and this network The road is the OP super chain.
At present, well-known institutions such as CoinBase, a16z, and BNB Chain have begun to create super chain networks based on OP Stack.
Native token: ETH
Governance Token: OP
Mainnet status: online
Extended reading: What is Optimism (OP Coin)? What is the OP Stack ecosystem?
Decision
Arbitrum is one of the most mature Optimistic Rollup solutions in the Ethereum ecosystem. It provides a high degree of EVM compatibility, allowing Ethereum dApps to be seamlessly ported to Arbitrum Layer2, achieving higher transaction throughput and lower gas fees. ARB is Arbitrum’s governance token.
Native token: ETH
Governance Token: ARB
Mainnet status: online
Extended reading: What is Arbitrum currency: popular ecological introduction, teaching, investment strategy
Starknet
Starknet belongs to the zk-Rollup type and was developed by StarkWare. It uses efficient Stark zero-knowledge proof to verify Layer2 transactions. Unlike other zk-Rollups, it is inherently EVM compatible.
Native token: ETH
Governance Token: Unknown
Mainnet status: online
Extended reading: What is StarkNet currency | Airdrop tutorial, ecological introduction
zkSync
zkSync is the representative project of zk-Rollup, created by Matter Labs. It focuses on providing high-speed, low-cost and private transactions for Ethereum. However, the zkSync project has also seen many controversies in the past, such as on-chain data fraud, Run away soft rug and so on.
Native token: ETH
Governance Token: Unknown
Mainnet status: online
Extended reading: What is zkSync: Token airdrop, operation tutorial, ecological introduction
Polygon zkEVM
Polygon zkEVM is a zk-Rollup solution launched by the originally well-known public chain project Polygon, which will provide Polygon with the dual advantages of EVM and zkRollup.
Native token: ETH
Governance Token: MATIC
Mainnet status: online
Extended reading: What is the Polygon chain | Introduction to future potential, exchanges, and ecology | zkEVM development
Scroll
Scroll is another zk-Rollup solution that uses unique ZK nodes for enhanced security and focuses on EVM-compliant environments. Scroll has now progressed to the last test network Sepolia, and the main network is expected to be launched this year.
Native token: ETH
Governance Token: Unknown
Mainnet status: under testing
Extended reading: What is the Scroll chain: token airdrop, operation tutorial, ecological introduction
Linea
Linea is also one of the zk-Rollup solution projects. It was created by Consensys, the development team behind MetaMask. It is a very influential Ethereum development company in the market. Currently, the network has been preset in the popular wallet Metamask, and users can directly Perform related interactions.
Native token: ETH
Governance Token: Unknown
Mainnet status: online
Extended reading: What is Linea chain | Token airdrop, wallet teaching, ecological interaction
Base
Base is an Ethereum Layer 2 network launched by Coinbase and supported by Optimism’s OP Stack, which provides a high-speed, secure and low-cost trading environment.
Utilize the CoinBase team's rich experience in cryptographic products to develop a complete ecosystem and provide a new DeFi environment to the Ethereum developer community and existing Coinbase users.
Native token: ETH
Governance Token: Unknown
Mainnet status: online
Further reading: CoinBase: What is the Base chain? Is there an airdrop? Wallet tutorial
Mantle
Mantle Network is a Layer 2 network launched by "BitDAO", one of the top decentralized autonomous organizations in the market. It uses OP Stack technology provided by Optimistic Rollups to provide a faster and cheaper transaction experience than Ethereum. And use modular blockchain design to create larger-scale performance.
Native token: MNT
Governance Token: MNT
Mainnet status: online
Extended reading: What is Mantle Netwrok: Token, ecological introduction, and relevance to BitDAO/Bybit?
opBNB
opBNB is the Layer2 solution officially launched by BNB Chain. It is built with OP Stack and is part of BNB Chain’s important network upgrade plan. It can achieve transaction speeds of up to 10,000 TPS. opBNB will significantly improve the performance of the BNB ecosystem.
Native token: BNB
Governance Token: Unknown
Mainnet status: under testing
Further reading: What is opBNB? Are there any token airdrops? BNB Chain’s L2 expansion plan
in conclusion
It is foreseeable that with the gradual upgrade of ETH 2.0, Layer 2 solutions will play an increasingly important role; however, the current problem of the blockchain is that there are too few actual users.
Even though these projects have their own characteristics, and each project is supported by well-known investment institutions, the competition among them will become increasingly fierce, such as OP Stack, ZK Stack, zkEVM series, etc., and there may only be a few projects by then. The project may emerge from it and become the cornerstone of the Ethereum ecosystem.
Of course, as these Layer 2 are expected to reshape the usage scenarios of public chains, they will have the opportunity to become the foundation supporting the Metaverse and Web3 world in the future. This will also be the key to achieving large-scale adoption and commercial application of blockchain technology.
