Layer 2 protocols (such as Hydra) build on top of a Layer 1 to add throughput or specialized behavior without changing the base chain's rules.
The base blockchain protocol itself, where transactions are finalized and the consensus rules are enforced; Cardano is a Layer 1.
Layer 2 protocols (such as Hydra) build on top of a Layer 1 to add throughput or specialized behavior without changing the base chain's rules.