The Internet Protocol Family

The most widely used set of communications protocols in the UNIX world is the Internet Protocol family, commonly known as TCP/IP. The name TCP/IP comes from two of the important protocols in the family, the Transmission Control Protocol (TCP) and the Internet Protocol (IP). Altogether, more than 100 different protocols are defined in this suite of protocols. The Internet Protocol family can be used to link together computers of many different types, including PCs, workstations, minicomputers, and mainframes, running different operating systems, over local area networks and wide area networks.

TCP/IP was developed and first demonstrated in 1972 by the United States Department of Defense (DoD) to run on the ARPANET, a DoD wide area network. Today the ARPANET is part of the Internet, another WAN, which connects millions of computers all over the world. The term “Internet” is commonly used to refer to both the network and the protocol suite.