While the full node is still a mostly passive participant of the protocol, they follow the chain by receiving and verifying every block in the chain. It maintains a full state of the blockchain by executing the extrinsics in blocks. Their role in the consensus mechanism is limited to following the chain and not producing the blocks.

Functional Requirements:

The node must populate the state storage with the official genesis state, elaborated further in Section A.3.3..

The node should maintain a set of around 50 active peers at any time. New peers can be found using the discovery protocols (Section 4.4.)

The node should open and maintain the various required streams (Section 4.7.) with each of its active peers.

Furthermore, the node should send block requests (Section 4.8.3.) to these peers to receive all blocks in the chain and execute each of them.

The node should exchange neighbor packets (Section 4.8.7.1.).