The Evolution Of Tcp Ip (And The Internet

The Evolution Of Tcp/Ip (And The Internet Essay, Research Paper

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 TCP/IP. The original versions of both TCP and IP that are in common use today were written in September 1981, although both have had several modifications applied to them (in addition, the IP version 6, or IPv6, specification was released in December 1995). In 1983, the DoD mandated that all of their computer systems would use the TCP/IP protocol suite for long-haul communications, further enhancing the scope and importance of the ARPANET.

In 1983, the ARPANET was split into two components. One component, still called ARPANET, was used to interconnect research/development and academic sites; the other, called MILNET, was used to carry military traffic and became part of the Defense Data Network. That year also saw a huge boost in the popularity of TCP/IP with its inclusion in the communications kernel for the University of California s UNIX implementation, 4.2BSD (Berkeley Software Distribution) UNIX.

In 1986, the National Science Foundation (NSF) built a backbone network to interconnect four NSF-funded regional supercomputer centers and the National Center for Atmospheric Research (NCAR). This network, dubbed the NSFNET, was originally intended as a backbone for other networks, not as an interconnection mechanism for individual systems. Furthermore, the “Appropriate Use Policy” defined by the NSF limited traffic to non-commercial use. The NSFNET continued to grow and provide connectivity between both NSF-funded and non-NSF regional networks, eventually becoming the backbone that we know today as the Internet. Although early NSFNET applications were largely multiprotocol in nature, TCP/IP was employed for interconnectivity (with the ultimate goal of migration to Open Systems Interconnection).

The NSFNET originally comprised 56-kbps links and was completely upgraded to T1 (1.544 Mbps) links in 1989. Migration to a “professionally-managed” network was supervised by a consortium comprising Merit (a Michigan state regional network headquartered at the University of Michigan), IBM, and MCI. Advanced Network & Services, Inc. (ANS), a non-profit company formed by IBM and MCI, was responsible for managing the NSFNET and supervising the transition of the NSFNET backbone to T3 (44.736 Mbps) rates by the end of 1991. During this period of time, the NSF also funded a number of regional Internet service providers (ISPs) to provide local connection points for educati