58.1. Internets

An internetwork or, more commonly, internet (with a lowercase i), connects different computer networks, allowing hosts on all of the networks to communicate with one another. In other words, an internet is a network of computer networks. The term subnetwork, or subnet, is used to refer to one of the networks composing an internet. An internet aims to hide the details of different physical networks in order to present a unified network architecture to all hosts on the connected networks. This means, for example, that a single address format is used to identify all hosts in the internet.

Although various internetworking protocols have been devised, TCP/IP has become the dominant protocol suite, supplanting even the proprietary networking protocols that were formerly common on local and wide area networks. The term Internet (with an uppercase I) is used to refer to the TCP/IP internet that connects millions of computers globally.