The Bitcoin network
The Bitcoin network is a peer-to-peer (P2P) network where nodes perform transactions. They verify and propagate transactions and blocks. Nodes called miners also produce blocks. There are different types of nodes on the network. The two main types of nodes are full nodes and simple payment verification (SPV) nodes. Full nodes, as the name implies, are implementations of Bitcoin Core clients performing the wallet, miner, full blockchain storage, and network routing functions. However, it is not necessary for all nodes in a Bitcoin network to perform all these functions. SPV nodes or lightweight clients perform only wallet and network routing functionality.
Versioning information is coded in the Bitcoin client in the version.h
file, which is available here: https://github.com/bitcoin/bitcoin/blob/0cda5573405d75d695aba417e8f22f1301ded001/src/version.h#L9.
Some nodes are full blockchain nodes with a complete blockchain as they are more secure and...