The history and development of Internet originated from ARPAnet established by ARPA, the predecessor of DARPA. The network was put into use on 1969. Since 1960s, ARPA has been providing funds to computer departments of American universities and some private limited companies to promote the research of computer networks based on packet switching technology. 1968, ARPA established the ARPAnet network project. The leading idea of this project is that the network must be able to withstand the test of failure and keep working normally. In the case of war, when a part of the network loses its working ability due to an attack, other parts of the network should be able to maintain normal communication. Initially, ARPAnet was mainly used for military research purposes. It has five characteristics: (1) supporting the enjoyment of resources; ⑵ Using distributed control technology; (3) adopting packet switching technology; (4) using a communication control processor; 5] Using layered network communication protocol. 1972, ARPAnet first met with the public at the first international conference on computer background communication, which verified the feasibility of packet switching technology. Therefore, ARPANET has become the symbol of the birth of modern computer networks. Another important contribution of ARPAnet in technology is the development and use of TCP/IP protocol family. 1980, ARPA invested in adding TCP/IP to the kernel of UNIX (BSD version 4. 1). After BSD version 4.2, TCP/IP protocol became the standard communication module of UNIX operating system. 1982, the internet was formed by the merger of ARPAnet, MILNET and other computer networks. ARPAnet, as the early backbone network of the Internet, tested and laid the foundation for the existence and development of the Internet, and solved a series of theoretical and technical problems in the interconnection of heterogeneous computer networks. 1983, ARPAnet was split into two parts: ARPAnet and MILNET, which were purely military. In June, 5438+that year 10, ARPA took TCP/IP protocol as the standard protocol of ARPAnet. Later, people called the Internet with ARPAnet as the backbone network, and the TCP/IP protocol family was studied and tested in the Internet and improved into a convenient and efficient protocol family. At the same time, the emergence and vigorous development of local area network and other wide area networks have played an important role in the further development of the Internet. One of the most striking is the National Science Foundation Network NSFnet (1986) established by the National Science Foundation of the United States. In order to make scientists and engineers all over the country enjoy these supercomputer facilities, NSF has established its own computer network NSFnet based on TCP/IP protocol suite. NSF has established computer wide area networks divided by regions throughout the country, and connected these regional networks with supercomputing centers, and finally interconnected supercomputing centers. The composition of a local area network is generally composed of a group of computers that are geographically confined to a certain area, belong to an organization in management or have the same interests in economy. The high-speed data line connecting the computers of the main communication nodes on the local area network constitutes the backbone network of NSFnet. In this way, when a user's computer is connected to a certain area, he can not only use the facilities of any supercomputer center, but also communicate with any user on the network to obtain the network. This success enabled NSFnet to completely replace ARPAnet and become the backbone of the Internet in June 1990. NSFnet's greatest contribution to the Internet is to make the Internet open to the whole society, instead of being used only by computer researchers, government employees and government contractors as before. However, with the rapid growth of online traffic, NSF has to adopt newer network technology to meet the needs of development. 1September, 990, Merit, IBM and MCI jointly established a non-profit organization-Advanced Network and Science Company ANS(Advanced Network & amp； The purpose of. ANS is to build a T3 backbone network in the United States, which can transmit data at a rate of 45Mb/s, which is equivalent to transmitting 1400 pages of text information per second. As of 199 1, all backbone networks of NSFnet have been connected with T3 backbone network provided by ANS. 1969 65438+February, when ARPAnet was first built, there were only four nodes; By March 1972, there were only 23 nodes; By March 1977, there were only 1 1 nodes. However, in recent ten years, 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 has become more and more obvious, and people's information awareness and emphasis on the development and utilization of information resources have strengthened, which has effectively stimulated the development of ARPAnet and NSFnet. The number of hosts and users connected to 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. From 65438 to 0994, almost all Internet software is guaranteed by TCP/IP protocol. 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. ● The scale of the Internet has become the largest international computer network at present. Today, the Internet has connected more than 60,000 networks and officially connected 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%. ● The future of the Internet From the current situation, the Internet market still has great development potential, and its future application will cover a wide range of fields, from office information to marketing and services. 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. However, the Internet also has its inherent shortcomings, such as no overall planning and design, unclear network expansion structure, and lack of fault tolerance and reliability, which are very important for many applications in the commercial field. Security is another big factor that puzzles the development of Internet users. Although there are many schemes and protocols to ensure reliable online business transactions on the Internet, the technologies and products that are really applicable and will dominate the market are still unclear. In addition, the Internet is a non-central network. These problems have hindered the development of the Internet to some extent. Only by solving these problems can the Internet develop better.