Internet is a collection of global information resources. There is a rough saying that the Internet is a logical network composed of many small networks (subnets), and each subnet is connected with several computers (hosts). Internet is based on some common protocols and is formed through many routers and public Internet for the purpose of exchanging information resources with each other. It is a collection of information resources and resources. 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 SNSFnet. 1988, SNSFnet 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 the Advanced Network Service Company (SNS) and established a new network called SNSnet, which became another backbone network of the Internet. It is different from SNSFnet, which is funded by the state and owned by SNS company, thus commercializing the Internet. On April 30th, 1995, SNSFnet 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. At present, there are different opinions about the exact time when the Internet came into being. Some people think that the successful demonstration networking of 1972 ARPANET marks the birth of the Internet. Others regard 1993 as the time when all networks connected with ARPAnet realize the conversion to TCP/IP. But in any case, the emergence of the Internet is not an isolated and accidental phenomenon, it is the inevitable result of people's constant pursuit of the ideal of information resources, so the origin of the Internet can be traced back to an earlier time. In recent decades, mankind has made one important progress after another in this regard, laying the foundation for the emergence of the Internet. For example, in 1957, the first artificial satellite went into the sky, which improved the ability of human beings to spread information to an unprecedented extent and opened a new era of satellite communication. In the 1970s, the appearance of microcomputers indicated that it was possible to popularize information technology. The use of laser and optical fiber technology has expanded the processing and dissemination of information from "point" to "surface". In recent ten years, the combination of computer and communication technology, especially the development of network technology, has promoted a wider range of network interconnection and information resource sharing. According to the literature, the first person who proposed information exchange through the Internet was J.C.R. Licklid of MIT. 1In August, 962, he put forward the concept of "giant network" in the article "Online Man-Machine Communication", and imagined that everyone could quickly obtain data and information anywhere through a globally interconnected facility. In terms of its spiritual essence, this network concept is very similar to today's Internet. Licklid was the first leader of the Advanced Research Projects Agency (ARPA) of the US Department of Defense. His successors, B. Taylor and L. G. Roberts, were convinced of the importance of this network concept and made important contributions to its further development and perfection. The development of packet switching theory Internet began with the early research on packet switching and related technologies. L Klein Rock of MIT published the first paper on packet switching theory in 196 1 and the first book on this theory in 1964. Packet switching mainly refers to dividing long information into several packets and transmitting them in communication networks. Each package is like an envelope, which contains the information to be delivered, the address to be delivered to the destination, and a number representing the position of the package in the whole information flow. Any lost or blocked packets can be retransmitted. When all data packets arrive at the destination, the receiver will reassemble these digital data blocks into complete information. This kind of network called "packet switching" can make multiple computers use the same communication line, or make a data stream pass through a crowded line and quickly pass through other paths. The theory of using packet instead of line for communication is an important step towards network technology. Another important development is to enable computers to transmit information to each other. Coincidentally, almost like the Massachusetts Institute of Technology (1961-kloc-0/967), the British National Physics Laboratory (1964- 1967) also conducted similar research, and they didn't know each other's research. Military computer network ARPAnet Internet is developed on the basis of military computer network ARPAnet. ARPANET is the earliest and most typical example of computer network. It is an experimental network jointly developed by the US Department of Defense and some university researchers in the late 1960s. At that time, considering the military defense strategy, the U.S. Department of Defense thought that a centralized management network was very fragile and could not withstand the destruction of nuclear war and other emergencies, and it was necessary to establish a huge network that could operate without relying on a single "central control computer" so that the whole communication system would not stop running because a certain part of the network was destroyed. More importantly, this network is an autonomous and self-regulating computer internet, which allows computers with different storage technologies and different operating systems to interconnect. Therefore, the US Department of Defense provided funds for this research to the then Advanced Research Projects Agency of the Department of Defense, which promoted ARPAnet to enter the experimental network from theoretical research. The further development of ARPANET is due to the fact that people engaged in this research find that it provides a very convenient communication channel. Initially, only four hosts were connected to the network. 1970 network working group (NWG) completed the initial ARPAnet host-to-host communication protocol, called network control protocol (NCP), under the leadership of S. Crocker. 1972, B. Kahn successfully organized a large-scale ARPAnet demonstration at the International Computer Communication Conference (ICCC), which was the first public appearance of this new network technology. In the same year, the Internet Working Group (INWG) led by CERF was announced to establish an Internet communication protocol. The idea of open network structure was put forward by B. Kahn shortly after 1973 to the Advanced Research Projects Agency of the US Department of Defense. The research project at that time was called "Internet Research Project". In order to meet the needs of the open network structure environment, V. CERF and B. Kahn jointly developed the TC P/IP protocol, which was formally put forward in 1974. When ARPAnet developed from experimental network to practical network, its operation management was handed over to DCA in 1975. 1982, the National Defense Communications Bureau and the Advanced Research Projects Agency decided to use TCP/IP, that is, transmission control protocol and network interconnection protocol, as the ARPANET communication protocol. This is the first time that "Internet" is a collection of Internet. In the first 10 year of its development, ARPAnet was mainly used to promote the development of e-mail, support online discussion groups, allow access to remote databases and support file transfer among government agencies, companies and universities. 1990 ARPANET stopped running after completing its historical mission. Throughout the 1970s, although ARPAnet, a military computer network, extended its reach to some major universities in the United States, it did not attract much interest due to technical and financial reasons. The real development of the Internet began in the mid-1980s, when the National Science Foundation (NSF) established the NSFnet network by using the technology of ARPAnet network. About 1984 At the request of some major research institutions of the U.S. government, the National Science Foundation of the United States took over the network expansion of advanced planning research institutions. NSFnet was originally composed of five interconnected supercomputer centers, and on this basis, it was further networked with major regions and major universities and research institutions in the United States. By 1986, NSFnet had initially formed a three-level network consisting of backbone network, regional network and campus network. 1984- 1989, NSFnet experienced a period of rapid development, and at the same time began to expand into business and broader fields, and gradually connected with other countries and regions. By the early 1990s, NSFnet had been transformed into a private enterprise, but the US government still supported the development of this network. 1992, several internet organizations merged to form the internet association ISOC. At this point, this network started from the military communication network, and then developed into a national academic research and education network through NSFnet, and began to expand to a wider field and a wider region, which is the second important milestone in the development of the Internet. In the 1990s, the World Wide Web adopted Hypertext Markup Language (HTML), a hypertext Internet protocol that can obtain Internet image information, so that everyone can create their own image pages (websites) and then become a part of a huge virtual hypertext network. This enhanced Internet, also informally known as the World Wide Web, has generated a large number of new users. So many people use the word "internet" to refer to the physical structure of this network, including clients, servers and telephone lines connecting everything; The word "World Wide Web" refers to all websites and information that can be accessed by using this network. In addition to supporting the National Science Foundation to establish the backbone network NSFnet, the US government has successively introduced and implemented several other policies, which have played a positive role in promoting the formation of the Internet and the proposal of the information superhighway. 1995 10 year 10 On 24th October, the Federal Network Council (FNC) of the United States passed a resolution to define the Internet as follows: "Internet" is a global information system, and (1) is based on the Internet Protocol (IP) and its extended protocols, and is made by the world. (2) Being able to support communication using transmission control protocol and Internet protocol (TCP/IP) and its extended protocols or other IP compatible protocols; (3) Providing opportunities to use or obtain high-level services openly or privately through communication and related infrastructure. This may be a clear definition of the Internet so far. With the development of social science, technology, culture and economy, especially the great development of computer network technology and communication technology, the trend of human society's transition from industrial society to information society is becoming more and more obvious. People's information awareness and attention to the development and utilization of information resources are constantly improving, which has effectively stimulated the development of ARPAnet and NSFnet, and the number of hosts and users connecting these two networks has increased dramatically. 1988, the number of computers connected to NSFnet soared to 56,000, and then it developed at an amazing speed of 2 to 3 times every year. 1994, the number of hosts on the internet reached 3.2 million, connecting 35,000 computer networks in the world. At present, there are more than 50 million Internet users, and the number is increasing at the rate of 10- 15% every month. Experts predict that by 1998, the number of Internet users will exceed 100 billion, and by 2000, there will be more than 100 billion networks in the world. Today's Internet is no longer a field for computer personnel and military departments to conduct scientific research, but a global information ocean for developing and utilizing information resources. On the Internet, there are more than 65,438+000 kinds of businesses, including advertising companies, airlines, agricultural production companies, arts, navigation equipment, bookstores, chemicals, communications, computers, consulting, entertainment, finance and trade, various shops, hotels and so on, covering all aspects of social life and forming a microcosm of an information society. From 65438 to 0995, the Internet began to be widely used in the commercial field. In that year, the total revenue of Internet business in the United States was $654.38+0 billion, and it is estimated that it will reach $654.38+0.8 billion in 1996. Online service providers have also developed from computer companies such as AOL and ProdigyService to AT & amp； Communication operators such as T, MCI and Pacific Bell also joined in. Due to the huge demand for commercial applications, the Internet application market, from modems to web servers and browsers, is booming. With the rapid development of the Internet, its product structure has also changed with the shift of users' needs. In 1994, almost all internet software is TCP/IP protocol package. At that time, people needed a network architecture compatible with TCP/IP protocol. Nowadays, the focus of the Internet has turned to specific applications, such as using WWW to advertise or conduct online transactions. Web is the fastest growing application on the Internet, with the number of users increasing from less than 4 million in 1994 to 1995. The number of websites ranges from 1995 to 30000. Internet has become the largest international computer network at present. Today, the Internet has connected more than 60,000 networks and 86 countries. E-mail can reach more than 65,438+050 countries, with more than 4.8 million hosts connected through it and more than 25 million users. The daily information flow reaches more than one trillion bytes, and the monthly e-mail exceeds 654.38+0 billion. At the same time, the application of the Internet has penetrated into various fields, from academic research to stock trading, from school education to entertainment games, from online information retrieval to online home shopping, and has made great progress. According to statistics, at present, in the domain name distribution of the Internet, Com-that is, commerce accounts for the largest proportion, accounting for 41%; . EDU-(science and education) takes a back seat, accounting for 30% of the total. In the growth of the Internet last year, the growth of the business sector accounted for 75%. However, in some Asian countries, the authorities try to block the connection between the national network and the international network, and their blocking network technology exceeds that of developed countries. This is undoubtedly a reversal of history. This section has great potential for future development. Judging from the current situation, the Internet market still has great development potential. In the future, its application will cover a wide range of fields, from office information sharing to marketing and service. In addition, the e-commerce brought by the Internet is changing the traditional mode of business activities today, and the convenient and extensive interconnection it provides will certainly have an impact on all aspects of future social life. The future Internet is very different from the present Internet, and it will be a large and small Internet. When you want to take it with you, you don't have to carry a big backpack to put it in. Instead, you can make it smaller, put it in your pocket, take it out anytime and anywhere, and open the Internet to help you search for the information you need. (The above information comes from Baidu).