History of the Technology, Chapter 4: 1972-1984

This era saw continued advances in communications technology, especially in computer networking and optical transmission. This period also brought about the introduction of intelligence into the public switched telephone network, beyond that which was required to complete a call to a dialed termination. The basic concept was to interrupt the processing of a call for accessing a database which contained information on how that call should be completed. The first use came in routing 800 calls, but many other applications followed. Common channel signaling via data channels and data switches was the underlying technology. This common signaling network was separate from the network conveying the communications message per se. Also, during these years the federal government began, and saw through to completion, anti-trust proceedings against AT&T in 1984 the Bell System's monopoly which had been sanctioned for more than seventy years, came to a close.

Between 1972 and 1983 ARPANET underwent two significant transformations: it became a network of networks, or an Internet, and it began to realize its commercial potential. At the end of 1971 ARPANET entered service with fifteen sites connected to the network. At this point, ARPANET incorporated and embodied many significant advances in computer networking techniques, hardware, and software; however, usage remained low. Though a great technical achievement, it could hardly be considered successful if nobody used it. In 1972 Robert Kahn and Lawrence Roberts decided to demonstrate the ARPANET's capabilities at the first IEEE International Conference on Computer Communications (ICCC), held in October in Washington, DC. This demonstration made a powerful impression on the thousand or so attendees. The Washington demonstration marked the point at which telephone engineers, steeped in a culture of circuit switching, began to accept packet switching as a workable communications methodology. The ICCC demonstration also marked a turning point in the use of the system. Traffic on the ARPANET jumped 67% during the month of the conference and maintained high growth rates afterward. As more and more users entered the ARPANET they began to reshape it toward their own purposes. Although ARPANET's architects envisioned it as a system to facilitate resource sharing like remote file access and time-sharing, it soon became apparent that its most popular use was electronic mail.

The enthusiastic response among communications specialists and the large increase in traffic on the network encouraged some ARPANET contractors to leave BBN and to start the first commercial packet switching company. In 1972 they started Packet Communications, Inc., to market an ARPANET-like service. BBN also launched its own networking subsidiary, Telenet Communictions Corporation, and Lawrence Roberts left ARPA to become its president. Telenet was the first network to reach the marketplace, and it began service in seven U.S. cities in August 1975.

In addition to limited commercialization of network services, over the course of the next decade the ARPANET, a single network that connected a few dozen sites, would be transformed into the Internet, a system of many interconnected networks capable of almost indefinite expansion. The Internet would far surpass the ARPANET in size and influence and would introduce a new set of techniques to computer networking. However, like electronic mail, the development of the Internet was not part of ARPA's initial networking plans.

The transformation of the ARPANET into the Internet owed a great deal to the work of ARPA researchers Robert Kahn and Vinton Cerf. The Internet architecture which they proposed gained widespread acceptance because it was decentralized and flexible enough to accommodate a range of uses and users. After Lawrence Roberts left ARPA to head Telenet, (BBN's commercial spinoff of the ARPANET), Robert Kahn, a prominent BBN researcher, joined IPTO as program manager. The major challenge which Kahn and Cerf faced was the design of a communications protocol which was flexible enough to permit interconnection with a wide variety of computers.

In June 1973 Cerf organized a seminar at Stanford University to address the design of the proposed Internet and its host protocol, the Transmission Control Protocol (TCP), and a year later the initial version of TCP was specified. BBN developed a version of TCP for its TENEX operating system by November 1975, and also in that year successfully connected its in-house research network to the ARPANET. Stanford also implemented TCP in 1975, and in November the Stanford and BBN groups set up an experimental TCP connection between their sites. BBN also began installing experimental gateways to test TCP over satellite links in 1976 and 1977. These early efforts not only proved out the basic concept of TCP, but also revealed flaws and deficiencies which pointed the way to further improvement.

By late 1977 the various networks and test sites were ready to try out the improved TCP. Experimenters sent packets from a van on a California freeway through packet radio to an ARPANET gateway, to a satellite networking gateway on the east coast, by satellite to Europe, and finally back through the ARPANET to the van in California. This demonstration confirmed the feasibility of the Internet scheme and showed how connections between radio, telephone, and satellite networks could be used for networking.

To improve the flexibility of the communication protocol, in January 1978 Vinton Cerf, Jon Postel, and Danny Cohen proposed splitting TCP into two components: a host-to-host protocol within networks (TCP) and an internetwork protocol (IP). The pair of protocols became known as TCP/IP. IP would pass individual packets between machines (for instance, from host to packet switch, or between packet switches), while TCP would be responsible for ordering these packets and providing reliable connections between hosts. Over the next five years ARPANET architects refined TCP/IP and in March 1981 they decided to replace the existing Network Control Program with TCP/IP on all ARPANET hosts. By June 1983 every host was running TCP/IP.

After converting the ARPANET to TCP/IP, ARPA took two more steps to set the stage for the later development of a large-scale civilian Internet. One step was to separate the ARPANET's military users and academic researchers, who had been coexisting somewhat uneasily since the Defense Communications Agency had taken over the network in 1975. This separation, which hived off a military network called MILNET, occurred in April 1983. The second step was to commercialize Internet technology, particularly the TCP/IP protocol. All the major computer companies took advantage of this opportunity, and by 1990 TCP/IP was available for virtually every computer on the United States market. This ensured that TCP/IP would become the de facto networking standard.

Between 1972 and 1983 ARPANET underwent a number of significant transformations: the entire network switched to TCP/IP, the military users left for their own network, and the ARPANET became part of a larger system -- the Internet. The field of computer networking underwent a conceptual transformation: instead of thinking about how to connect individual computers together, network builders also had to consider how different networks could interact with each other. By 1984 the fledgling Internet connected over 100 universities and research facilities in the United States and Europe.

Just as the ARPANET and early Internet demonstrated the feasibility of large-scale computer networking, several significant projects in the mid and late 1970s proved the value of optical fibers for communications. In 1975 AT&T Bell Laboratories installed an experimental optical fiber trunk system in Atlanta, GA, using a 650 m 144-fiber cable in a loop configuration. The fibers could be interconnected to simulate longer transmission lengths. Bell Labs engineers carried out a full range of system experiments at a data rate of nearly 45 Mb/s and obtained unrepeatered spacings up to 11 km with an error rate less than 10-9 and negligible crosstalk. Thus the Atlanta experiment established the practicability of all aspects of optical fiber trunk transmission, including the performance of the fiber itself, its installation, splicing, transmitters and receivers, electronics, optical jacks and jumpers, and overall system performance.

The success of the 1975 Atlanta experiment led to the installation of a similar system in the spring of 1977 in Chicago's Loop. In September 1980, a second system entered service in the Atlanta-Smyrna region of Georgia, US. AT&T also installed major long-haul routes, including a 776-mile route from Moseley, VA to Cambridge, MA and a 500-mile route from Los Angeles to San Francisco. By the end of 1982 more than 150,000 km of cabled fibers had been installed in the Bell System, and a year later that figure had risen to more than 300,000 km of cabled fibers capable of data rates of 45 or 90 Mb/s. Finally, in 1982 and 1983 AT&T Bell Labs began testing of undersea light wave systems, a research and development program which would culminate in a transatlantic fiber cable, TAT-8, in 1988.

Japan's Nippon Telephone & Telegraph (NTT) also aggressively pursued optical fiber technology in this period. In 1978 NTT conducted a major field test involving 168 subscribers using fibers to bring broadband services to homes, including a very broad range of video services such as two-way video. NTT placed an 80-km trunk route into service in 1983, capable of carrying 400 Mb/s. After the successful installation of this system NTT announced plans for more than 60 such installations totalling nearly 100,000 km of fiber.

Alongside of these major developments in the fields of computer networking and optical fibers, a major shakeup in the American telecommunications industry began: the beginning of the breakup of the Bell System. In 1974 the Department of Justice filed an antitrust suit against AT&T. Federal regulators wanted to force AT&T to allow interconnects to its system, competition in the long-distance market, and the purchase of telephone equipment on the open market instead of from its subsidiary Western Electric. After ten years, hundreds of millions of dollars, and millions of pages of documents, AT&T and the Justice Department came to an agreement: the Justice Department allowed AT&T to keep Western Electric, but directed it to divest itself of all the local operating companies.

On 1 January 1984 AT&T exited the local telephone business, spinning off seven regional Bell operating companies (RBOCs). AT&T kept its long-distance operations, Western Electric, and Bell Labs,and it began to move into non-regulated businesses such as computing. A research and systems engineering organization, later known as Bellcore, was established by the divestiture agreement. It provided technical support to the newly-formed regional telephone companies on a shared ownership basis. In its original form, Bellcore was a major force in the communications industry, doing applied research and developing network plans and generic requirements for the elements required to build and operate those networks. Bellcore has since been acquired by SAIC, and now provides its services to a wide spectrum of clients beyond the original seven regional companies. Deregulation spurred competition and lowered prices in the long-distance market, but created some confusion among consumers. Before the breakup, 80% of the public said that they were satisfied with their telephone service; in 1985 64% of Americans thought divestiture was a bad idea and many called for the reunification of AT&T. Deregulation also eroded the preeminent position of Bell Labs as a leading research center in basic engineering and science. Under the AT&T monopoly, Bell Labs depended on a protected source of operating revenue and its researchers enjoyed a great degree of independence. This environment helped Bell Labs researchers to win 7 Nobel Prizes since the 1920s, more than any other organization in the world, and to undertake far-reaching work in many areas of electrical engineering and basic science. Thus, while the breakup of AT&T offered the telecommunications consumer more choices and lower costs, it also eroded an important component of the nation's research infrastructure.

Chapter 5: 1985-2002