ARPANET

The Advanced Research Projects Agency Network (ARPANET) 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. These technologies became the technical foundation of the Internet. The ARPANET was created by the Advanced Research Projects Agency (now DARPA) of the United States Department of Defense.

Building on ideas from J. C. R. Licklider, Bob Taylor started the ARPANET project in 1966. The goal was to allow resource sharing between computers far apart. The first computers were connected in 1969, and the network began working in 1971. It grew quickly and allowed early forms of email and file transfer.

In the early 1980s, ARPANET started using Version 4 of TCP/IP. This made it possible for many networks to connect and form a larger network of networks. The ARPANET was officially stopped in 1990, after helping to create what we now know as the Internet.

Inspiration

The telephone network used a system where each call needed a direct connection. In the early 1960s, Paul Baran at the RAND Corporation suggested a new way to keep communications working, even if there were problems. Around the same time, Donald Davies at the National Physical Laboratory in the United Kingdom thought of a similar idea called packet switching.

In 1963, J. C. R. Licklider from Bolt Beranek and Newman wrote about a network for computer users, calling it the Intergalactic Computer Network. When he joined the Advanced Research Projects Agency, he encouraged others, like Ivan Sutherland and Bob Taylor, to develop this idea. Taylor thought one network could help people connect to different computers more easily. Davies' work on packet switching helped create the ARPANET, one of the first networks to use this technology.

Creation

In 1966, a man named Bob Taylor got money from the U.S. government to start a new kind of computer network called ARPANET. He hired Larry Roberts to help with the project. They worked with many experts to decide how the network would work.

In 1969, a company called BBN built the first version of ARPANET. It used small computers to connect bigger computers together. This network helped computers talk to each other over long distances and was the beginning of what we now call the Internet.

Main article: ARPANET

Implementation

The first four nodes of the ARPANET were set up to test the 1822 protocol. They connected in 1969, but network use began in 1970 with the Network Control Program. This allowed the first two ways to talk to other computers: remote login (Telnet) and file transfer (FTP). The network started working in 1971, and more people used it when email became popular around 1973.

The first four hosts linked UCLA, ARC, UCSB, and the University of Utah School of Computing. The first node was at UCLA, where researcher Leonard Kleinrock tested how well the network worked. The places were chosen to save money and because each had special skills. The first connection was made between Stanford Research Institute (SRI) and UCLA on October 29, 1969. The first lasting connection was made on November 21, 1969. By December 5, 1969, the four-node network was finished.

The ARPANET kept getting bigger. By 1970, it reached the East Coast of the United States. More parts called IMPs (Interface Message Processors) were added, and the network grew to include more universities and government hosts. By 1973, there were 40 IMPs, and by 1975, the network had 57 IMPs. The network was shown at an international conference in October 1972.

Networking evolution

The ARPANET was the first wide-area network to use packet switching and distributed control. It was created by the Advanced Research Projects Agency of the United States Department of Defense. The network used special computers called IMPs to send messages between different computers. Each IMP had a short number, and each computer connected to an IMP also had a small number. Together, these numbers made up an address that helped messages find their way to the right computer.

As the network grew, new ways to send messages were developed. One early method was called the 1822 protocol, which helped different kinds of computers talk to each other. Later, a new system called the Network Control Program (NCP) made it easier for many different programs on a computer to communicate over the network. Finally, researchers created a more advanced system called TCP/IP, which allowed many different kinds of networks to connect together. This became the foundation of the Internet we use today.

Main article: ARPANET

Operation

The ARPANET began as a research project about communication. It was not for everyday users at first. By 1975, control of the network moved to the Defense Communications Agency. Special devices were added to keep secret information safe.

In 1981, the National Science Foundation helped more people use it through the Computer Science Network.

Later, the ARPANET connected with networks in Norway and the UK. By 1980, the Department of Defense chose TCP/IP to help military computers communicate.

In 1984, the military made its own network called MILNET. This made the ARPANET smaller, but it kept working for research.

Applications

The ARPANET let different programs share services on one computer. This created special rules, called application protocols, that worked apart from the network’s main services. Key protocols were TELNET for remote access and File Transfer Protocol (FTP) for sending files and early email.

In the 1970s and 1980s, new ways to send messages were created. Ray Tomlinson made the first network e-mail in 1971, and email quickly became a big part of ARPANET traffic. Later, Simple Mail Transfer Protocol, POP, and IMAP made email better. Voice calls tried to use the Network Voice Protocol, but they did not work well at that time.

Security

The ARPANET, the first wide-area computer network, needed ways to keep information safe. In 1971, a special method called the Purdy Polynomial was created to help protect passwords. This method used math to create a unique code for each password. Later, a big tech company named Digital Equipment Corporation used this same method to protect passwords in their VMS operating system, and it’s still used today for that purpose.

Main article: [Purdy Polynomial]

Rules and etiquette

The ARPANET was paid for by the government, so there were rules about its use. People could send personal messages to each other, but they were not allowed to use it for business or politics.

In 1978, Gary Thuerk from Digital Equipment Corporation sent the first mass email to many possible customers. This showed how powerful email could be for marketing, even though it was not allowed. The network had strict rules to make sure it was only used for government work.

Decommissioning

In 1985, a new project called NSFNET started to help universities and government agencies connect. By 1990, the ARPANET, the first network that helped start the Internet, was turned off. Some of its old machines were still used until July.

On February 28, 1990, when the ARPANET was shut down, Vinton Cerf, a leader in Internet development, wrote a poem to honor it. He called it "Requiem of the ARPANET," celebrating the ARPANET’s important role in creating the Internet we use today.

Legacy

The ARPANET was very important for creating modern computer networking, including the Internet. It introduced new ideas like packet switching and decentralized networks. These ideas helped make a global network that changed how we talk and share information.

Many research projects were connected to the ARPANET. Senator Al Gore helped pass a bill in 1991 to support the growth of the National Information Infrastructure, which he called the information superhighway. The ARPANET received two IEEE Milestones in 2009. In 2011, a historical marker was placed in Arlington County, Virginia, to honor the early beginning of the Internet.