What is an optimistic rollup?
The Ethereum network has become increasingly strained as more and more people sign up for cryptocurrency. This is why we use the Layer 2 (L2) blockchain solution. It helps individuals with the wait time, which means they don’t have to wait longer for lower transaction fees. It also allows for increasing the scale of the Ethereum blockchain.
Why do we need an L2 solution?
Ethereum users must pay a high gas fee to transact on the network. There is an overwhelming volume of transactions on the network. Due to the large volume, only the users who can afford to pay for transactions go through faster than other network users. The blockchain delegates some work to other network layers by introducing a multi-layer system. The Layer 2 solution provides
Rollups
Rollups provide solutions to Ethereum congested problems. Rollups execute the transactions off-chain to reduce the burden on Ethereum. They then combine the results of multiple off-chain transactions, put them into a compressed file to reduce the size, and post this compressed file on the Ethereum blockchain.
Optimistic rollups extend the throughput rate associated with the base layer of the Ethereum blockchain. Optimistic rollups are used to stimulate the efficiency of the Ethereum network by executing the off-chain transaction to reduce the load and make the Ethereum network less congested. When an optimistic rollup posts a compressed file, the blockchain optimistically believes that all the transactions contained in the file are valid. It does not verify that a transaction has been executed correctly.
There is a delay when moving the transaction from optimistic Ethereum to the Ethereum blockchain. Delays keep the transactions safe. Optimistic rollups use a fraud-proof window (also known as a challenging period). This fraud-proof window is a time after transaction results have been displayed. During this time, a user may challenge that the demonstrated results were incorrect. This delay should be long enough to ensure that all fraudulent transactions are detected and rectified to maximize safety.
The time it takes to verify a transaction batch in an optimistic rollup can vary depending on the specific implementation and the number of transactions in the batch. In general, the time it takes to verify a batch of transactions in an optimistic rollup is much faster than the time it would take to verify the same transactions on the main chain. This is because the off-chain computations are done in parallel, and the verification process is simplified by the use of a fraud-proof window. Optimistic rollups easily allow developers to migrate their applications from Layer 1 to roll up almost seamlessly.