Protocols & Platforms
Layer 2
Layer 2 Scaling Solution
Scaling system deriving settlement security from its layer 1
Definition
An Ethereum layer 2 executes activity off mainnet while deriving settlement security from Ethereum. Rollups publish transaction data and use fault or validity proofs. Sidechains use their own consensus: Polygon PoS is a sidechain/commit-chain, not an Ethereum rollup.
Example
If a hypothetical rollup spreads a $10 batch-posting cost across 1,000 transactions, that component costs $0.01 each. Execution, compression and sequencer charges still affect the total fee.
How it works
A sequencer orders transactions and publishes batches or commitments to Ethereum. Rollup proofs let the settlement contract validate the resulting state; the exact exit and upgrade assumptions depend on the implementation.
Risks to Consider
- A sequencer outage can delay transactions or withdrawals
- Upgrade keys can change bridge or proof rules
- Proof and data-availability failures can compromise exits
Common Questions
Are all Ethereum scaling chains rollups?
No. A rollup is one L2 design; a sidechain such as Polygon PoS has its own validator security. EVM compatibility is not proof of Ethereum-equivalent security.
