A long-running debate in computer science known as the Protocol Wars occurred from the 1970s to the 1990s when engineers, organizations and nations became polarized over the issue of which communication protocol would result in the best and most robust computer networks. This culminated in the Internet–OSI Standards War in the 1980s and early 1990s, which was ultimately "won" by the Internet protocol suite (TCP/IP) by the mid-1990s and has since resulted in most other protocols disappearing.
The pioneers of packet switching technology built computer networks to research and provide data communications in the late 1960s and early 1970s. As more networks emerged in the mid to late 1970s, the debate about interface standards was described as a "battle for access standards". An international collaboration between several national postal, telegraph and telephone (PTT) providers and commercial operators agreed to the X.25 standard in 1976, which was adopted on public data networks providing global coverage. Separately, proprietary data communication protocols also emerged, most notably IBM's Systems Network Architecture and Digital Equipment Corporation's DECnet.
The United States Department of Defense developed and tested TCP/IP during the 1970s in collaboration with universities and researchers in the United States, United Kingdom and France. IPv4 was released in 1981 and the DoD made it standard for all military computer networking. By 1984, an international reference model known as the OSI model had been agreed upon, with which TCP/IP was not compatible. Many governments in Europe – particularly France, West Germany, the United Kingdom and the European Economic Community – and also the United States Department of Commerce mandated compliance with the OSI model and the US Department of Defense planned to transition away from TCP/IP to OSI.
Meanwhile, the development of a complete Internet protocol suite by 1989, and partnerships with the telecommunication and computer industry to incorporate TCP/IP software into various operating systems laid the foundation for the widespread adoption of TCP/IP as a comprehensive protocol suite. While OSI developed its networking standards in the late 1980s, TCP/IP came into widespread use on multi-vendor networks for internetworking and as the core component of the emerging Internet.
Early computer networking
Packet switching vs circuit switching
Computer science was an emerging discipline in the late 1950s that began to consider time-sharing between computer users and, later, the possibility of achieving this over wide area networks. In the early 1960s, J. C. R. Licklider proposed the idea of a universal computer network while working at Bolt Beranek & Newman and, later, leading the Information Processing Techniques Office (IPTO) at the Advanced Research Projects Agency (ARPA, later, DARPA) of the United States Department of Defense (DoD). Independently, Paul Baran at RAND in the United States and Donald Davies at the National Physical Laboratory (NPL) in the United Kingdom invented new ideas for the design of computer networks. Baran published a series of briefings and papers about dividing information into "message blocks" and sending them over distributed networks between 1960 and 1964. Davies conceived of and named the concept of packet switching using interface computers for data communication in 1965-6. He proposed a national commercial data network in the UK and designed the local-area NPL network to demonstrate and research his ideas. The first use of the term protocol in a modern data-communication context occurs in an April 1967 memorandum entitled A Protocol for Use in the NPL Data Communications Network written by two members of Donald Davies' team, Roger Scantlebury and Keith Bartlett.
Licklider, Baran and Davies all found it hard to convince incumbent telephone companies of the merits of their ideas. AT&T in the United States and the postal, telegraph and telephone service (PTT) in the United Kingdom, the General Post Office (GPO), had a monopoly on communications infrastructure. The telephone service operators believed speech traffic would continue to dominate data traffic and believed in traditional telegraphic techniques. Telephone companies were operating on the basis of circuit switching, the alternatives to which are message switching or packet switching.