The network only becomes useful when everyone on the network speaks the same language.
Letters are easy to address, obeying an agreed convention, and easy to put in a letter box.
Data goes into and out of the network at the node and is passed by the network from node to node without being stored or processed. Of course, like a computer, the network is not much use without any software tools to ease its use. We use three main types of network. The Ethernet specifications define the lowest level of communication protocol. Some care must be taken with Ethernet to prevent disrupting the work of others.