The network layer, also known as the P2P layer, is the one that is responsible for internode communication. It takes care of discovery, transactions, and block propagation. This layer can also be termed as propagation layer. This P2P layer ensures that nodes can discover each other and can communicate, propagate and synchronize with each other to maintain valid current state of the blockchain network. Visit the following Transaction flow subsection, in this chapter to experience the P2P layer in terms of transaction broadcast, transaction proposals, transaction validation and transaction commit. This layer also takes care of the world state propagation. A P2P network is a computer network where computers (nodes) are distributed and share the network’s workload to reach the end goal. Nodes perform transactions on the blockchain. There are two kinds of nodes—full node and light node. Full nodes ensure the verification and validation of transactions, mining, and the enforcement of consensus rules. They are responsible for maintaining trust in the network. Light nodes only keep the header of the blockchain (keys) and can send transactions.