What is Protocol Layer?

The protocol layer is made up of the underlying blockchain consensus mechanism and nodes which make up the foundation of the entire blockchain. This layer can also include different types of external Layer-2 blockchain systems such as sidechains, as well as virtual machines. More commonly, the protocol layer refers to the underlying architecture that all Layer-1 blockchain networks are made up of. The protocol layer is composed of addresses that identify specific nodes, error reporting, interface identification systems, network synchronization and state changes, and the sending, receiving, and processing of network transactions.