Web3 is the next-generation vision for a decentralized internet, leveraging blockchain technology's distributed ledger and smart contracts to provide a more secure, transparent, and decentralized digital world. However, with the rapid development of blockchain technology, a major challenge is network throughput and transaction processing speed. While the decentralized nature and immutability of blockchain are powerful, they fall short in terms of scalability. Particularly on popular blockchain platforms like Ethereum, high transaction costs and slow processing speeds have become bottlenecks affecting widespread adoption.

In this context, Layer 2 (L2) solutions have emerged as a scaling approach aimed at addressing blockchain network throughput issues, improving transaction speeds, and reducing costs. This article will delve into Layer 2 solutions in Web3 development, analyzing how they enhance network throughput, including the basic concepts, core technologies, application scenarios, and their impact on the Web3 ecosystem.

What is Layer 2?

Layer 2 refers to an additional protocol or framework built on top of the main blockchain (Layer 1), designed to expand the main chain's processing capacity by handling transactions and data externally. The core goal of Layer 2 is to address the scalability issues of Layer 1 blockchains, particularly by improving transaction speed and throughput under high concurrency while maintaining decentralization and security.

Layer 2 does not directly alter the core structure of the blockchain but establishes second-layer protocols through various technical means, moving some transaction computations and data storage off-chain, thereby reducing the on-chain data burden and enhancing the overall performance of the blockchain.

Why is Layer 2 Needed?

In blockchain networks, every node must validate transactions to ensure data consistency and security. As the network grows and transaction volume increases, Layer 1 blockchains often face the following issues:

1. Low Transaction Throughput: Blockchains like Ethereum have limited transaction throughput, processing only a few dozen transactions per second (TPS). This means that as users and applications increase, network congestion can occur, slowing transaction speeds and causing fees to surge.

2. High Transaction Fees: When network load is high, users must pay higher miner fees to ensure their transactions are processed quickly. This is a significant barrier for ordinary users and small developers.

3. Scalability Bottlenecks: The decentralization and security requirements of blockchains necessitate transaction validation by numerous nodes, creating immense computational and storage pressures that hinder large-scale expansion.

Therefore, Layer 2 solutions have emerged as effective means to enhance throughput and transaction speeds. By introducing Layer 2, blockchains can significantly improve performance while maintaining decentralization and security.

Common Layer 2 Solutions

Currently, there are various types of Layer 2 solutions, each with unique advantages and applicable scenarios. The main Layer 2 technologies include:

1. State Channels

State channels are a technology that reduces on-chain load by executing multiple transactions off-chain and submitting only the final result to the main chain. State channels allow two or more participants to conduct multiple transactions without intermediaries, with all transactions occurring off-chain, and only the final result (e.g., balance changes) being submitted to the main chain.

Advantages:

• High transaction execution speed.

• Low transaction costs.

• Enables instant transactions and micropayments.

Disadvantages:

• Suitable for small-scale transactions and simple application scenarios, not ideal for large-scale decentralized applications.

• Participants need to pre-deposit funds before transactions begin.

2. Plasma

Plasma is a Layer 2 solution proposed by Ethereum's Vitalik Buterin, aimed at expanding the main chain's throughput by creating child chains. Plasma transfers data storage and computational tasks from the main chain to multiple child chains, which interact with the main chain via smart contracts and periodically submit critical state information to the main chain.

Advantages:

• Enables parallel transaction processing on multiple child chains, significantly increasing throughput.

• Ensures security through a "fraud proof" mechanism.

Disadvantages:

• Plasma's exit mechanism is complex, and users may face delays when withdrawing.

• Implementation is complex for developers, requiring handling of inter-chain interactions and state validation.

3. Rollups

Rollups are one of the most prominent Layer 2 solutions today, particularly Optimistic Rollups and ZK-Rollups. Rollups batch process transaction data and submit the results to the main chain, significantly reducing the computational and storage burden on the blockchain.

(1) Optimistic Rollups:

Optimistic Rollups assume off-chain transactions are valid and only verify them if fraud is detected, greatly reducing on-chain computation and storage requirements.

(2) ZK-Rollups:

ZK-Rollups use zero-knowledge proofs (ZKPs) to validate the correctness of off-chain transactions. By proving the computation results are correct without disclosing transaction details, they enhance privacy and security.

Advantages:

• Extremely high transaction throughput, with ZK-Rollups capable of processing thousands of transactions per second.

• Significantly reduces transaction costs.

Disadvantages:

• ZK-Rollups technology is relatively complex, requiring the use of zero-knowledge proofs, making development and implementation challenging.

• Optimistic Rollups require a long "challenge period" to handle potential fraud.

4. Sidechains

Sidechains are independent blockchains connected to the main chain via a two-way peg. They can execute transactions and smart contracts independently but maintain security through interoperability with the main chain. By offloading some computational tasks to sidechains, Layer 2 performance can be enhanced.

Advantages:

• Customizable rules and structures for sidechains based on needs.

• Independent scalability, avoiding burden on the main chain.

Disadvantages:

• Lower security, especially in interactions between sidechains and the main chain.

• Maintaining multiple blockchains increases system complexity.

How Does Layer 2 Improve Throughput?

Layer 2 solutions effectively enhance blockchain throughput through the following methods:

1. Reducing On-Chain Transaction Volume

By moving most transaction processing off-chain, Layer 2 solutions significantly reduce the number of on-chain transactions, alleviating the main chain's burden and effectively increasing the number of transactions processed per second.

2. Parallel Transaction Processing

Some Layer 2 solutions, such as Plasma and Sidechains, support parallel processing of multiple transactions. By utilizing multiple child chains or sidechains, these solutions can handle large volumes of transactions simultaneously, greatly improving throughput.

3. Optimizing Computation and Storage

By moving transaction computation and storage tasks off-chain, Layer 2 solutions reduce the computational and storage pressure on the blockchain, enhancing transaction processing speed.

4. Batch Processing Transactions

Rollups combine multiple transactions into a single batch submitted to the main chain, reducing the main chain's burden and improving transaction processing speed.

Layer 2 Application Scenarios in Web3

Layer 2 solutions have broad application scenarios in the Web3 ecosystem:

1. Decentralized Finance (DeFi): DeFi applications require high throughput and low transaction costs, which Layer 2 can address to improve transaction efficiency.

2. NFT Marketplaces: NFT transactions involve frequent transfers and minting operations, and Layer 2 can provide fast transaction confirmations and low fees.

3. Cross-Chain Operations: Layer 2 solutions enable efficient cross-chain transactions between different blockchains.

4. Gaming and Micropayments: Blockchain games and micropayment applications require fast and low-cost transactions, which Layer 2 provides as an ideal solution.

Conclusion

The development of Web3 relies on efficient and scalable blockchain technology, and Layer 2 solutions undoubtedly provide strong support for addressing blockchain scalability issues. Through technologies like state channels, Plasma, and Rollups, Layer 2 effectively enhances blockchain transaction throughput, reduces costs, and offers technical assurance for the widespread adoption of decentralized applications. As technology continues to advance, Layer 2 solutions will mature further and play a crucial role in various Web3 application scenarios.