The Evolution of TCPIP and The Internet
The Evolution of TCP/IP (and the Internet)
While the TCP/IP protocols and the Internet are different, their evolution are most definitely parallel. This section will discuss some of the history.
Prior to the 1960s, what little computer communication existed comprised simple text and binary data, carried by the most common telecommunications network technology of the day; namely, circuit switching, the technology of the telephone networks for nearly a hundred years. Because most data traffic transmissions occur during a very short period of time, circuit switching results in highly inefficient use of network resources. In 1962, Paul Baran, of the Rand Corporation, described a robust, efficient, store-and-forward data network in a report for the U.S. Air Force; Donald Davies suggested a similar idea in independent work for the Postal Service in the U.K., and coined the term packet for the data units that would be carried. According to Baran and Davies, packet switching networks could be designed so that all components operated independently, eliminating single point-of-failure problems. In addition, network communication resources appear to be dedicated to individual users but, in fact, statistical multiplexing and an upper limit on the size of a transmitted entity result in fast, economical data networks.
The modern Internet began as a U.S. Department of Defense (DoD) funded experiment to interconnect DoD-funded research sites in the U.S. In December 1968, the Advanced Research Projects Agency (ARPA) awarded a contract to design and deploy a packet switching network to Bolt Beranek and Newman (BBN). In September 1969, the first node of the ARPANET was installed at UCLA. With four nodes by the end of 1969, the ARPANET spanned the continental U.S. by 1971 and had connections to Europe by 1973.
The original ARPANET gave life to a number of protocols that were new to packet switching. One of the most lasting results of the ARPANET was the development of a user-network protocol that has become the standard interface between users and packet switched networks; namely, ITU-T (formerly CCITT) Recommendation X.25. This "standard" interface encouraged BBN to start Telenet, a commercial packet-switched data service, in 1974; after much renaming, Telenet is now a part of Sprint's X.25 service.
The initial host-to-host communications protocol introduced in the ARPANET was called the Network Control Protocol (NCP). Over time, however, NCP proved to be incapable of keeping up with the growing network traffic load. In 1974, a new, more robust suite of communications protocols was proposed and implemented throughout the ARPANET, based upon the Transmission Control Protocol (TCP) and Internet Protocol (IP). TCP and IP were originally envisioned functionally as a single protocol, thus the protocol suite, which actually refers to a large collection of protocols and applications, is usually referred to simply as...