Last week we communicated that Tixl’s Autobahn Network will be an Optimistic Rollup. Not sure what a Rollup is?     A Rollup is a so-called “L2” or “Layer 2” or a scaling solution running on top of a “Layer 1” or “L1” network.   You usually distinguish between an “Optimistic Rollup” and a “ZK Rollup”.   Optimistic Rollups: They are very lightweight, scalable, and offer the ability to deploy the underlying data on chain very cheap. This makes them incredibly gas efficient and profitable at lower usage. The data gets published on the L1 without a proof attached and can be contested by others with so called fraud proofs.   ZK Rollups: The most significant difference is that when information gets published on the L1, the ZK Rollup attaches a Zero-Knowledge Proof to the transaction (A mathematical way to show that what they say is true) — to make it verifiable that the data is correct. This proof is costly in fees, making zk Rollups only profitable if they have very high user amounts or do specific transactions. Another consequence of the architecture is that you can’t run a regular EVM inside a zk Rollup yet, meaning you need to add a custom VM, making the compatibility less ideal.