What are Layer 1 and Layer 2 blockchains? How do they work?

Core Points

Layer 1 blockchain is an underlying network, such as Bitcoin and Ethereum, that independently manage transactions, security, consensus and blockchain data.

The Layer 2 solution runs on top of the Layer 1 network and is designed to increase transaction capacity, reduce fees and increase speed while avoiding overburdening the underlying blockchain.

Cross-chain bridges allow assets and information to flow between layers of the blockchain, but different designs introduce different security, decentralization and trust considerations.

Layer 1 and Layer 2 blockchains represent different parts of the blockchain architecture, with each layer playing a unique role in supporting decentralized networks. Layer 1 provides the underlying infrastructure to process transactions and maintain network security, while Layer 2 introduces additional extension mechanisms designed to improve performance.

Networks including Bitcoin, Ethereum and Solana operate as Layer 1 blockchains because their protocols maintain their own ledgers and consensus systems. However, with the popularity of blockchain applications, problems such as congestion, slow transactions and rising costs may arise when the volume of activity exceeds the capacity of these basic networks.

The Layer 2 solution solves these limitations by moving some activities away from the underlying blockchain while maintaining connectivity to Layer 1. As a result, technologies including Rollup and state channels can improve transaction throughput while reducing the computing burden on the underlying network.

What is Layer 1 blockchain?

Layer 1 blockchain is the primary network that forms the foundation of the decentralized blockchain ecosystem. Bitcoin, Ethereum, and Solana are all examples because they run independent networks responsible for verifying transactions, maintaining blockchain records, and enforcing their respective consensus rules.

The consensus mechanism is particularly important because it determines how network participants agree on effective transactions and the current state of the blockchain. Bitcoin uses proof of work, which requires computing resources to verify transactions and generate blocks. Ethereum uses proof of interest, and verifiers participate in network security maintenance by pledging cryptocurrency as collateral. These mechanisms help decentralized participants maintain a shared and tamper-resistant transaction history without relying on a centralized institution.

Despite providing core security infrastructure, Layer 1 networks may encounter scalability limitations when transaction needs increase significantly.

How does Layer 1 expansion work?

Layer 1 expansion involves modifying the underlying blockchain itself to improve its ability to process transactions. Different blockchain networks can adopt different methods based on their architecture and technical requirements. Increasing block capacity is a possible strategy because larger blocks can accommodate more transactions. Another approach is to improve consensus mechanisms to process transactions more efficiently without compromising network security. Sharping is another potential Layer 1 expansion technology. Rather than requiring the entire network to handle the same amount of work, sharding divides blockchain operations into smaller fragments, allowing them to process activities in parallel. However, blockchain developers must consider the relationship between scalability, decentralization, and security when introducing these improvements. Improving performance while maintaining other features remains an important challenge for Layer 1 networks.

What is Layer 2 blockchain?

Layer 2 refers to the expansion infrastructure built on top of the existing Layer 1 blockchain. These solutions do not replace the underlying network, but aim to leverage the characteristics of the underlying blockchain to increase transaction capacity. Layer 2 solutions are particularly important for blockchain networks that face a large amount of transaction activity. Moving some transaction processing away from Layer 1 can reduce congestion and potentially achieve faster transaction speeds and lower fees. Several Layer 2 methods have emerged, including state channels and Rollup. The status channel allows participants to conduct multiple transactions outside of the main blockchain and ultimately settle the resulting status on Layer 1. Rollup uses another method, which combines a large number of transactions and submits summary information to the underlying blockchain, thereby reducing the amount of data or calculations required for Layer 1 to directly process each transaction.

What is the difference between Layer 1 and Layer 2?

The main difference lies in where blockchain activities are processed. Layer 1 is the underlying blockchain and is responsible for consensus, security, and maintaining the network's main transaction ledger. Layer 2 runs on top of this infrastructure and focuses on improving scalability and transaction efficiency. Layer 2 does not need to have every transaction fully processed by the underlying blockchain, but instead processes or aggregates activities before interacting with Layer 1. Therefore, these two layers can complement each other. Layer 1 provides the foundation of the blockchain ecosystem, while Layer 2 expands the amount of activity that can be supported without requiring every transaction to consume the same foundation layer resources.

How does the blockchain cross-chain bridge connect Layer 1 and Layer 2?

The blockchain cross-chain bridge provides the infrastructure to transfer assets and information between Layer 1 and Layer 2 environments. They are particularly important because assets held by users on the underlying blockchain may need to be transferred to the Layer 2 ecosystem before they can interact with applications running on that layer. Cross-chain bridges can adopt different security models. Trust-free cross-chain bridges typically rely on smart contracts and blockchain mechanisms to coordinate transfers without requiring centralized intermediaries; trusted cross-chain bridges rely on an entity responsible for overseeing part of the transfer process. These designs involve different trade-offs in terms of security, speed, decentralization and trust. Therefore, cross-chain bridges play an important role in interoperability, but may also introduce additional technical considerations beyond the use of a single blockchain.

How does the cross-chain bridge from Ethereum to Arbitrum work?

Transferring ether or ERC-20 tokens between Ethereum and Arbitrum is an example of Layer 1 and Layer 2 interaction. Users who want to transfer assets can interact with the cross-chain bridge contract on Ethereum and send relevant tokens to the contract. These tokens are locked on Ethereum, and the corresponding number of tokens will be available to users in the Arbitrum ecosystem. Assets can then be used on Arbitrum, where transactions are often more efficiently processed than directly on the Ethereum foundation layer. Arbitrum processes transactions in batches and regularly submits information to Ethereum, allowing the Layer 2 network to benefit from the security of the underlying blockchain. When users want to transfer assets back to Ethereum, they need to initiate withdrawals from Arbitrum. Corresponding Layer 2 assets will be locked or removed, and the original assets can eventually be released on Ethereum after going through the required withdrawal process and challenge period.

What are the advantages of Layer 2 blockchain?

Scalability is one of the main advantages of Layer 2 technology. Processing activities outside of the basic blockchain can significantly increase the number of transactions supported by the ecosystem. Lower transaction costs are another potential advantage because the Layer 2 system can spread settlement fees at the base layer across multiple transactions. This makes blockchain applications more practical for users who conduct frequent transactions or have small amounts of money. Layer 2 networks can also improve the user experience by reducing transaction delays during periods of high demand for the underlying blockchain. These capabilities are becoming increasingly important for decentralized applications, including decentralized financial platforms and NFT ecosystems, where users may perform a large number of blockchain transactions.

What are the potential risks of Layer 2 blockchain?

Layer 2 networks introduce additional complexity as users interact with infrastructure outside the underlying blockchain. Therefore, the security characteristics of a particular solution depend in part on its architecture and relationship to Layer 1. Cross-chain bridges may present another area of risk because assets moving between different blockchain environments rely on mechanisms that control deposits, withdrawals, and asset representation mechanisms. Some systems may also introduce a greater degree of centralization based on how transactions are processed, verified, or moved across networks. Therefore, users need to understand the security and trust assumptions associated with each Layer 2 solution. In addition, the existence of numerous Layer 2 networks may decentralize blockchain liquidity and applications across different environments, increasing the need for reliable interoperability infrastructure.

Conclusion

Layer 1 and Layer 2 blockchains serve complementary functions in the blockchain ecosystem. The Layer 1 network (including Bitcoin and Ethereum) provides the basic infrastructure for consensus, security, transaction settlement and blockchain data, while Layer 2 solutions focus on improving scalability and transaction efficiency. Technologies, including state channels and Rollup, reduce congestion by moving activities away from the underlying blockchain and ultimately interacting with Layer 1. Cross-chain bridges further connect these environments by allowing assets and information to move between different blockchain layers. However, expanding blockchain networks involves trade-offs in terms of security, decentralization, interoperability and technical complexity. Therefore, Layer 2 is an extension of Layer 1's infrastructure rather than a replacement for the underlying blockchain. As blockchain applications attract more transaction activity, the relationship between Layer 1's security and Layer 2's scalability may remain at the core of supporting efficient decentralized networks.

Frequently Asked Questions

1. What is Layer 1 blockchain?

Layer 1 blockchain is a fundamental decentralized network responsible for processing transactions, maintaining their ledgers, running their consensus mechanisms, and ensuring the security of blockchain activities.

2. What is Layer 2 blockchain?

Layer 2 is a scale-up infrastructure running on top of the Layer 1 blockchain that aims to increase transaction capacity, reduce congestion, and reduce transaction costs.

3. What are the examples of Layer 1 blockchain?

Bitcoin, Ethereum and Solana are all examples of Layer 1 networks because they each run their own underlying blockchain and consensus infrastructure.

4. What are some examples of Layer 2 expansion solutions?

Layer 2 expansion methods include state channels and Rollup, which move or aggregate transaction processing away from the underlying Layer 1 blockchain.

5. How are Layer 1 and Layer 2 blockchains connected?

Layer 1 and Layer 2 networks can interact through cross-chain bridges and settlement mechanisms that enable assets, transaction information and other data to move between blockchain environments.