L2 network nodes consist of several parts, with the sequencer being the most critical. However, Rollup sequencers currently face centralization issues. Based Rollup represents a significant shift in Ethereum Layer 2 scaling by delegating Rollup sequencing directly to Layer 1 proposers. Utilizing the proposer-builder separation design, Layer 1 performs all sequencing roles for Rollup. Additionally, it extends MEV, allowing L2 searchers to bundle transactions and send them to L2 builders, who are also L1 searchers. These complete L2 blocks then become part of L1 blocks, ultimately processed by L1 builders and the Ethereum mainnet.