In the late 1960s, it was during the Cold War. At that time, the US military established a military network called "ARPAnet" by the Advanced Research Projects Agency (ARPA) of the US Department of Defense, so as to keep communication with the rest of the computer network when it was attacked. ARPANET was officially opened in 1969. At that time, only four computers were networked for scientists to carry out computer networking experiments. This is the predecessor of the Internet.
By 1970s, ARPAnet had dozens of computer networks, but each network could only communicate with computers in the network, and different computer networks still could not communicate with each other. To this end, ARPA has established new research projects to support academic and industrial research. The main content of the research is to connect different computer local area networks with a new method to form "Internet". Researchers call it "Internet", or simply "Internet". This term has been used to this day.
In the process of studying and realizing interconnection, computer software plays a major role. 1974, protocols for connecting packet networks appeared, including TCP/IP, the famous Internet protocol IP and transmission control protocol TCP. These two protocols cooperate with each other, in which IP is the basic communication protocol and TCP is the protocol to help IP realize reliable transmission.
A very important feature of TCP/IP is openness, that is, the specification of TCP/IP and the technology of Internet are open. The purpose is to make computers produced by any manufacturer interoperable and make the Internet an open system. This is an important reason for the rapid development of the Internet.
ARPA accepted TCP/IP in 1982, chose Internet as the main computer communication system, and converted other military computer networks into TCP/IP. 1983, ARPAnet is divided into two parts: one part is military, called MILNET；; The other part is still called civil ARPANET.
From 65438 to 0986, the National Science Foundation (NSF) interconnected five supercomputing centers serving scientific research and education in the United States, supported regional networks, and formed NSFnet. 1988, NSFnet replaced ARPAnet as the backbone of the Internet. The backbone network of NSFnet uses TCP/IP technology which has been proved to be very successful in ARPAnet, and allows the network of universities, governments or private scientific research institutions to join. 1989, ARPANET was dissolved and the Internet changed from military to civilian.
The development of the Internet has aroused great interest from businesses. 1992, three American companies, IBM, MCI and MERIT, jointly established Advanced Network Service Company (ANS) and established a new network called ANSnet, which became another backbone network of the Internet. It is different from NSFnet, which is funded by the state, while ANSnet is owned by ANS company, thus commercializing the Internet.
On April 30th, 1995, NSFnet officially announced that it would stop operating. At this time, the backbone network of Internet has covered 9/kloc-0 countries around the world, with more than 4 million hosts. In recent years, the Internet has developed at an alarming rate and soon reached today's scale.