Layer1

Layer 1 is a term used in multiple technical domains to denote the base layer of a system, the foundation on which everything else operates. In networking, it refers to the physical layer, while in blockchain contexts it refers to the base protocol and ledger. The common idea is that Layer 1 provides core rules, security, and data availability that higher layers build upon.

In networking and the OSI model, Layer 1, the Physical Layer, defines the electrical, optical, and radio characteristics of the transmission medium. It specifies how signals are carried over cables or wireless media and establishes bit timing, voltage levels, and connectors. Layer 1 does not interpret data; it hands raw bits to Layer 2, which handles framing and error detection.

In blockchain, Layer 1 networks are the base blockchains that implement the consensus mechanism, provide security, and host the native asset and smart contracts. They govern block production, data availability, and cross-chain interoperability. Notable Layer 1 platforms include Bitcoin, Ethereum, Solana, Avalanche, and Polkadot’s relay chain. Layer 2 solutions run atop Layer 1 to improve scalability and take advantage of Layer 1 security, such as rollups and sidechains.

Design considerations for Layer 1 include throughput, latency, security, decentralization, energy efficiency, and ecosystem maturity. Some networks prioritize high throughput and low fees, sometimes with trade-offs in decentralization or security, while others emphasize maximal decentralization and robustness. Ethereum’s transition from Proof of Work to Proof of Stake in 2022 is a landmark example of Layer 1 evolution, illustrating how base-layer protocols can change consensus mechanisms.