Optimistic

Optimistic Rollups operate on the assumption that all transactions are valid.
How it works
1. L2 operator(a.k.a Sequencer) broadcast Type 3 Transaction with Sidecar
  1. Coinbase(OP-Stack) BatchSender is L2 operator that has the tasks such as order, compression, batch.
Blobs 구조(Ethereum code, EIP-4844, Etherscan Example)
- Versioned hash: identifier
- Commitment and Proof: cryptographic proof for verification
트랜잭션 검증: fraud proof each time window.
- KZG commitment를 검증
- 문제 제기 시에만 L1에서 재검증. challenge 기간 존재 (Make sure it’s true)
Pros: much cheaper than legacy(using calldata)
Cons: finality

L2 OP-Stack: 검증된 효율성; 오픈소스, L1 보안을 유지 + 속도 상승, 수수료 절감(Blob), 결제 인프라(Ecosystem)

1. Arbitrum

Arbitrum Nova

Arbitrum AnyTrust Chain = Arbitrum AnyTrust Protocol

running on Ethereum mainnet with permissioned party as known DAC.

great for gaming.
Arbitrum One

Arbitrum Rollup Chain = Arbitrum Rollup Protocol

running on Ethereum mainnet; Fully trustless

great for De-Fi.
Arbitrum Nitro

The node in order to service and/or interact with an Arbitrum chain.

a fork of Geth to implement Arbitrum's state transition function and uses WebAssembly as its underlying VM for fraud proofs.