# Optimistic rollup

## Definition

An optimistic rollup is a Layer 2 system that generally treats posted transaction results as valid unless they are challenged during a defined dispute process.

## What it means in practice

Its security model relies on fraud-proof or challenge mechanisms and can create a waiting period for some canonical withdrawals to Ethereum.

## How this concept appears in Terenval Wallet

Terenval supports optimistic-rollup networks such as Arbitrum One and Optimism/Base as separate network contexts.

**Important:** Do not assume a withdrawal from an optimistic rollup to Ethereum has the same timing as an ordinary same-chain transfer.

**[Install Terenval Wallet](https://wallet.terenval.com/?lang=en)**

## Related terms

- [Rollup](https://wallet.terenval.com/glossary/rollup/)
- [Arbitrum](https://wallet.terenval.com/glossary/arbitrum/)
- [Optimism](https://wallet.terenval.com/glossary/optimism/)
- [Base](https://wallet.terenval.com/glossary/base/)
- [Withdrawal period](https://wallet.terenval.com/glossary/withdrawal-period/)
- [Canonical bridge](https://wallet.terenval.com/glossary/canonical-bridge/)

## Related Terenval Answers

- [Ethereum Layer 2 Networks and Gas Fees](https://wallet.terenval.com/answers/ethereum-layer-2-networks-and-gas-fees/)
- [Can One Crypto Wallet Manage Multiple Blockchains?](https://wallet.terenval.com/answers/can-one-crypto-wallet-manage-multiple-blockchains/)
- [How Does a Multi-Chain Crypto Wallet Keep Networks Separate?](https://wallet.terenval.com/answers/how-multi-chain-wallets-keep-networks-separate/)

## Sources

- https://ethereum.org/en/layer-2/
- https://wallet.terenval.com/info/supported-networks/

Official page: https://wallet.terenval.com/glossary/optimistic-rollup/