This tag should be used for questions relating to the protocols by which cryptocurrencies are transferred. This includes the network protocol and consensus rules.
The network protocol are the set of rules and messages that all Bitcoin nodes must follow in order to be able to connect to and communicate with each other. Details about how the Peer-to-Peer network protocol works can be found on bitcoin.org
The consensus protocol is the set of rules and procedures that a node must follow in order for it to accept the same blocks and transactions as all other nodes on the network.