ARPANET

The Advanced Research Projects Agency Network (ARPANET) was not the Internet itself. It was the first wide-area packet-switched network with distributed control. It was also one of the first computer networks to use the TCP/IP protocol suite. Both of these technologies became the technical foundation of the Internet. The Advanced Research Projects Agency (now DARPA) of the United States Department of Defense set up the ARPANET.

Bob Taylor started the ARPANET project in 1966. He built on the ideas of J. C. R. Licklider. The goal was to let computers that were far apart share resources, which is called resource sharing. Taylor chose Larry Roberts as the program manager. Roberts made important decisions about the request for proposal for building the network. He used the packet switching ideas of Donald Davies and asked for advice from Paul Baran. In 1969, the company Bolt Beranek & Newman (BBN) received the contract to build the Interface Message Processors (IMPs). Bob Kahn led the design and created the first protocol for the network.

The first computers were connected in 1969. The Network Control Program was put in place in 1970, and the network was declared working in 1971. Soon after, new software let people use remote login and file transfer. This gave an early form of email. The network grew quickly. In 1975, its control passed to the Defense Communications Agency.

Later, Bob Kahn and Vint Cerf worked together to create the Transmission Control Program for internetworking, which is the joining of networks. This work let separate networks connect into a network of networks. It drew on ideas from the French CYCLADES project, led by Louis Pouzin, and from Bob Metcalfe at Xerox Parc. TCP/IP version 4 started being used on the ARPANET on 1 January 1983. The ARPANET was officially shut down in 1990. By then, partnerships with the telecommunication and computer industry had helped the wider network, known as the Internet, grow and become commercial.

Inspiration

Early voice and data communications used circuit switching, like the traditional telephone network. Each call had its own dedicated connection between the two stations. In the early 1960s, Paul Baran at the RAND Corporation proposed new ideas for systems that could keep working even if some parts stopped working. Donald Davies at the United Kingdom's National Physical Laboratory (NPL) came up with a similar idea in 1965.

In April 1963, computer scientist J. C. R. Licklider of Bolt Beranek and Newman (BBN) wrote about an "Intergalactic Computer Network" that would let computer users communicate widely. Later that year, he became head of programs at the Advanced Research Projects Agency (ARPA). Ivan Sutherland and Bob Taylor continued developing the idea. They wanted researchers funded by ARPA to share computers and quickly send new software to one another. Taylor found it frustrating to use three separate computer terminals, which led to the idea that became the ARPANET. Davies' work also caught the attention of ARPANET developers in October 1967. In August 1968, he gave the first public presentation on packet switching, a term he created, and used it in the NPL network. The NPL network and the ARPANET were the first two networks in the world to use packet switching.

Creation

In February 1966, Bob Taylor convinced ARPA's Director Charles M. Herzfeld to fund a network project. Herzfeld moved one million dollars to Taylor's budget from a missile defense program. In January 1967, Taylor hired Larry Roberts to work on the ARPANET in the ARPA Information Processing Techniques Office. Roberts asked Frank Westervelt to study message size and contents for the network. At an April 1967 design session, technical standards were discussed. Wesley Clark then suggested using small computers called minicomputers as an interface for a message switching network. Roberts liked this idea and named them Interface Message Processors (IMPs). The plan was presented in October 1967 at the first Symposium on Operating Systems Principles. Other ideas about sending data in small pieces, called packet switching, came from Donald Davies and Paul Baran. A colleague, Roger Scantlebury, shared Davies's ideas at the meeting. By mid-1968, Roberts and Barry Wessler had written a final version of the IMP plan. It was based on a report from Stanford Research Institute (SRI). After approval, a Request for Quotation was sent out. In January 1969, ARPA chose BBN to build the network.

The BBN team was led by Frank Heart for the IMPs and Bob Kahn for the network's design. Other team members included Dave Walden, Severo Ornstein, William Crowther, and others. Their network used small IMP computers to connect local resources. This is similar to the later idea of routers. The IMPs were linked by leased lines through modems at a starting speed of 50 kbit/s. Host computers connected to them through special serial communication interfaces. The first IMPs used a rugged computer version of the Honeywell DDP-516. It had 24 KB of expandable magnetic-core memory and a direct memory access unit. The first network connected one computer in Utah with three in California. Later, the Department of Defense allowed universities to join, so they could share hardware and software over early Digital Signal 0 leased telephone lines.

Implementation

The first four computers on the network were used to test and fix the 1822 protocol, which was a big job. They were connected electronically in 1969. People could not yet run network programs until the Network Control Program was added in 1970. This allowed the first two ways for computers to work together: Telnet for logging in to a computer from far away, and FTP for sending files. The network was declared working in 1971. Traffic began to grow once email was set up at most sites by about 1973.

The first four sites were UCLA, ARC, UCSB, and the University of Utah School of Computing. At UCLA, Leonard Kleinrock studied how well the network worked and tested his ideas about message delay. On 29 October 1969, Charley Kline tried to log in from UCLA to a computer at the Stanford Research Institute. The system crashed after he typed two characters. After an adjustment, he logged in successfully. So the first two characters sent over the ARPANET were "lo". By 5 December 1969, the four-site network was in place. Elizabeth Feinler created the first Resource Handbook for ARPANET in 1969. This led to a directory that made it easier to find your way around the network.

By 1971, the network was growing. By 1973, it had reached more sites. In 1972, the ARPANET was shown at the International Conference on Computer Communications (ICCC). Networks were also studied using queueing theory and mathematical models developed by Kleinrock. These helped the ARPANET grow quickly in the early 1970s.

Networking evolution

The ARPANET's message processors, called IMPs, were built by BBN. They could pass messages to one another, which helped them route data and send it reliably. In 1969, host computers began talking to each other using the 1822 protocol. This protocol could not handle many connections at once, so a Network Control Program (NCP) was developed under Steve Crocker, with Jon Postel among the researchers. NCP let application software run across the network using communication protocols. This was an early step toward the OSI model. Computers at MIT also took part in these early networking efforts.

Starting in 1972, Louis Pouzin and Hubert Zimmermann in France worked on a simpler way to link networks, called a catenet. Bob Kahn and Vint Cerf led research that produced the Transmission Control Program in 1974. The International Network Working Group was also formed. Testing began the next year. The software was later redesigned as a modular Version 4 in 1978. It was installed on the ARPANET in January 1983, replacing NCP. By 1989, the Internet protocol suite was complete. It helped lay the foundation for the Internet.

Operation

ARPA was meant to pay for advanced research. The ARPANET was a research project. It focused more on how computers could communicate than on the people who used it. In the summer of 1975, control of the ARPANET passed to the Defense Communications Agency. Around that time, the first ARPANET encryption devices were set up to protect secret messages. A report from 1978, published in 1981 by BBN and DARPA, concluded that the ARPANET program had a strong effect on computer science, the field the network came from.

In 1981, the National Science Foundation (NSF) paid for the Computer Science Network (CSNET). This gave more people access to the ARPANET.

NCP gave computers on the ARPANET a shared set of network services that many programs could use. This led to application protocols, which are sets of rules for specific tasks. These protocols could mostly work on their own and could be improved without changing the network underneath. Programs such as TELNET, used for remote access to shared computers, and File Transfer Protocol (FTP) were later adapted to run over the TCP/IP protocol suite. Telnet was developed in 1969. Abhay Bhushan wrote the first FTP specification, which was published as an RFC in 1971. By 1973, FTP was defined and was being used to move files across the ARPANET.

In 1971, Ray Tomlinson of BBN sent the first network e-mail. A study by ARPA in 1973 found that about three-quarters of ARPANET traffic was email, and email stayed a very large part of it. In the 1980s, FTP was replaced for email by the Simple Mail Transfer Protocol, and later by POP and IMAP. The Network Voice Protocol (NVP) was defined and used in 1977, but because of technical problems, conference calls over the ARPANET never worked well. Sending voice as packets, which is known today as Voice over Internet Protocol, was still many years away.

Security

The Purdy Polynomial hash algorithm was created for the ARPANET in 1971 to help protect passwords. Larry Roberts, who led ARPA at that time, asked for it.

Later, Digital Equipment Corporation (DEC) used the algorithm to protect passwords in its VMS operating system. It is still used for this purpose today.

Rules and etiquette

The ARPANET was paid for by the government, so some kinds of use were discouraged or not allowed.

Leonard Kleinrock says he committed the first illegal act on the Internet. After a meeting in England in 1973, he sent a request to get his electric razor back. At that time, using the ARPANET for personal reasons was against the law.

In 1978, Gary Thuerk of Digital Equipment Corporation (DEC) broke the network's rules. He sent the first mass email to about 400 possible clients over the ARPANET. He says this brought in $13 million in sales of DEC products. It also showed how useful email marketing could be.

A 1982 handbook about computing at MIT's AI Lab said that using the ARPANET for anything that did not directly support government work was illegal. Personal messages, such as arranging a meeting or saying hello, were generally not seen as harmful. Sending emails for profit or politics was described as harmful to others and illegal. It could get MIT into serious trouble.

Decommissioning

In 1985, the NSF paid for national supercomputing centers at several universities. In 1986, it also provided network access and connections through the NSFNET project. NSFNET became the Internet backbone for government agencies and universities.

The ARPANET project was officially shut down in 1990. Its original machines were phased out as NSFNET came into use, though some were still running as late as July 1990. On 28 February 1990, the ARPANET was shut down. Afterward, Vinton Cerf wrote a poem called "Requiem of the ARPANET."

It was the first, and being first, was best, but now we lay it down to ever rest. Now pause with me a moment, shed some tears. For auld lang syne, for love, for years and years of faithful service, duty done, I weep. Lay down thy packet, now, O friend, and sleep.

— Vinton Cerf

Legacy

The ideas and technology from the ARPANET helped shape modern computer networking, including the Internet. Packet switching, networks without a single central control point, and rules for how computers talk to each other laid the groundwork for a worldwide network. This network changed how people communicate, share information, and do research together. Many other research projects were connected to the ARPANET. Some helped shape its design, some were side projects, and some grew out of it.

Senator Al Gore wrote the High Performance Computing and Communication Act of 1991, often called "The Gore Bill." He was inspired by a 1988 plan for a National Research Network. A group led by Leonard Kleinrock had sent that plan to Congress. The bill passed on 9 December 1991. It led to the National Information Infrastructure, which Gore called the information superhighway. The ARPANET project received two IEEE Milestones in 2009. On 17 May 2011, Arlington County, Virginia, put up two historical markers about the internet's beginnings. They stand at 1400 Wilson Boulevard in the Rosslyn neighborhood, where the agency was based from 1970 to 1975.

Charles Herzfeld, who led ARPA from 1965 to 1967, said the ARPANET was not started to build a command and control system that could keep working after a nuclear attack. Many people now believe it was. He said the network grew from a problem: the country had few large research computers, and many researchers who needed them were far away. The ARPANET shared its work across many computers and often updated the paths data took. This made it better able to keep working when parts of it failed. The Internet Society agrees with Herzfeld. It notes that the idea about surviving a nuclear war came from an earlier study by RAND about secure communication. Paul Baran first proposed a theory for packet switching, and he did that RAND study. The ARPANET did not share his goal, but Baran said his work helped its development. Notes from Elmer Shapiro of Stanford Research Institute suggest that a version of his routing method might have been used.

Later, in the 1970s, ARPA did place more focus on "command and control." Stephen J. Lukasik was deputy director from 1967 to 1970 and director of DARPA from 1970 to 1975. He explained that the goal was to use new computer technology to meet military command and control needs and to improve military decision making.