Since the birth of Ethereum in 2015, its ecosystem has been increasingly enriched with the rapid development of DeFi, NFT, and games. However, at the same time, the scalability of the Ethereum network cannot meet the rapidly growing demand as it can only process about 15 transactions per second, resulting in high transaction fees and pricing out a lot of users.
In order to scale Ethereum, developers have proposed 2 solutions, namely, Layer 2 and sharding (a Layer 1 scaling solution).
Layer 1 refers to the Ethereum blockchain itself, and Layer 2 is a network or technology that operates on top of Ethereum to improve its scalability and efficiency.
Mainstream Layer 2 projects include Arbitrum, zkSync, Optimism, etc.