Internet is a great milestone in the development of human history and the embryonic form of the future information superhighway, from which human beings are entering an unprecedented information society. People call the Internet by various names, such as Internet, Internet, Internet and so on. It is expanding and spreading to all continents in the world, constantly adding and absorbing new network members, and has become the computer information network with the widest coverage, the largest scale and the richest information resources in the world.
The development of the Internet has roughly gone through the following five stages:
1, the origin of the Internet
In a sense, the internet can be said to be the product of the cold war between the United States and the Soviet Union. The origin of such a huge network can be traced back to 1962. At that time, the U.S. Department of Defense believed that in order to ensure that the U.S. domestic defense forces and overseas defense forces still had a certain ability to survive and counterattack after the first nuclear attack in the former Soviet Union, it was necessary to design a decentralized command system: it consisted of decentralized command points. When some command points were destroyed, other points could still work normally, and these points could continue to keep in touch by bypassing those destroyed command points. In order to verify this idea, in 1969, the Defense Advanced Research Projects Agency (DoD/DARPA) of the US Department of Defense funded the establishment of a network called ARPANET, which connected the hosts of the University of California, Los Angeles, the University of California, Santa Barbara, Stanford University and Utah State University in Salt Lake City, and the large computers at each node were grouped. This ARPANET is the earliest prototype of the Internet.
By 1972, there are 40 nodes on ARPANET, and these 40 nodes can send small text files (then called E-mail, which is our current e-mail) and large text files, including data files (now FTP on the Internet) to each other. At the same time, it is found that a remote computer can be used by simulating a computer as the terminal of another remote computer. It can be seen that e-mail, FTP and Telnet are important tools that appeared earlier on the Internet, especially e-mail is still the most important application on the Internet at present.
The emergence of the 2.TCP/IP Agreement.
1972, experts and scholars in the computer and communication industries all over the world held the first international computer communication conference in Washington, USA, and reached an agreement on communication between different computer networks. The general assembly decided to set up an Internet working group to work out a standard specification (namely "communication protocol") that can guarantee communication between computers. From 65438 to 0973, the United States Department of Defense also began to study how to realize the interconnection between different networks.
By 1974, IP (Internet Protocol) and TCP (Transmission Control Protocol) came out, collectively known as TCP/IP protocol. These two protocols define the method of transmitting messages (files or commands) between computer networks. Subsequently, the U.S. Department of Defense decided to provide TCP/IP to the world unconditionally and free of charge, that is, to announce the core technology to solve the communication between computer networks to the world. The disclosure of the core technology of TCP/IP protocol has finally contributed to the great development of the Internet.
By 1980, there are both ARPA networks using TCP/IP protocol by the US military and many other communication protocols in the world. In order to connect these networks, American Winton CERF put forward an idea: each network uses its own communication protocol and uses TCP/IP protocol when communicating with other networks. This idea eventually led to the birth of the Internet and established the unshakable position of TCP/IP protocol in network interconnection.
3. The "Spring and Autumn Period and Warring States Period" of the Internet.
In the late 1970s and early 1980s, it was the Spring and Autumn Period and the Warring States Period of the Internet, and various networks came into being.
In the early 1980s, DARPANet was a great success, but schools that didn't get contracts from American federal agencies still couldn't use it. In order to solve this problem, the National Science Foundation (NSF) began to establish a computer science network (CSNet) for the computer departments of universities. CSNet is a logical network formed by adding a unified protocol layer to other basic networks. It uses the communication capabilities provided by other networks, and it is also an independent network from the user's point of view. CSNet adopts centralized control mode, and all information exchange is carried out through CSNet-Relay (a relay computer).
1982, Steve Bellovin of North Carolina State University founded a famous collector communication network-newsgroup. Any user in this network can send information (messages or articles) to other users on the Internet, and everyone can discuss their concerns with others on the Internet. 1983 ——Bitnet, a discussion network of City University of new york, also appeared. In this network, different topics are divided into different groups, and users can subscribe by computer according to their own needs. This network was later called mailing list. 1983, another network FidoNet (Fido BBS), namely bulletin board system, was born in San Francisco, USA. Its advantage is that users can send emails and discuss problems with each other as long as they have computers, modems and telephone lines. This is the later Internet BBS.
All these networks have merged into the Internet and become a part of it, so the Internet has become a large collection of all kinds of networks in the world.
4. The foundation of the Internet-NSFNET
The first rapid development of Internet originated from the intervention of National Science Foundation (NSF), that is, the establishment of NSFNET.
In the early 1980s, a large number of scientists in the United States called for the popularization of computer and network resources in order to improve the infrastructure construction in the fields of education and scientific research and resist the challenges and competition of advanced education and scientific and technological progress in Europe and Japan.
In the mid-1980s, the National Science Foundation (NSF) encouraged universities and research institutions to enjoy their four expensive supercomputers, and hoped that the computers of universities and research institutions would be connected with these four supercomputers. At first, NSF tried to use DARPANet as the main communication line of NSFNET, but due to its military nature and control by government agencies, this decision was unsuccessful. So they decided to use the TCP/IP communication protocol developed by ARPANET to build a WAN named NSFNET.
1986, NSF invested in the establishment of five supercomputing centers, namely Princeton University, Pittsburgh University, University of California, San Diego, University of Illinois and Cornell University, and the prototype of NSFNET was formed through 56Kbps communication lines. 1987 NSF invited public bidding for the upgrade, operation and management of NSFNET. As a result, IBM, MCI and Merit, a non-profit organization composed of several universities, won the NSF contract. 1In July 1989, the communication line speed of NSFNET was upgraded to T 1 (1.5 Mbps), and 13 backbone nodes were connected. Communication lines provided by MCI and routing equipment provided by IBM are adopted, and Merit is responsible for the operation and management of NSFNET. Encouraged and funded by NSF, many universities, government-funded and even private research institutions have incorporated their local area networks into NSFNET. From 1986 to 199 1, the number of subnets of NSFNET has rapidly increased from 100 to more than 3,000. The official operation of NSFNET and its connection with other existing and new networks have really become the foundation of the Internet.
The expansion of the Internet in 1980s not only brought quantitative changes, but also brought some qualitative changes. Due to the entry of various academic groups, enterprise research institutions and even individual users, Internet users are no longer limited to pure computer professionals. New users find communication between computers more attractive to them. Therefore, they gradually regard the Internet as a tool for communication, rather than just enjoying the computing power of NSF supercomputers.
In the early 1990s, the Internet has actually become an "Internet": each subnet is responsible for its own erection and operation costs, and these subnets are interconnected through NSFNET. NSFNET connects tens of millions of computers in the United States and has tens of millions of users. It is the most important member network of the Internet. With the expansion and diffusion of computer networks around the world, networks outside the United States are gradually connected to the backbone network or its subnets of NSFNET.
Internet future
Now the Internet is developing very fast, and its scale is gradually expanding, but the speed is still very slow. Although the broadband rate has reached OC- 12(622Mbps), the end-to-end rate between two computers accessing the Internet through local area network is only 40Kbps, which is only equivalent to the data transmission rate between a pair of Modem, which is obviously not enough to support many new application requirements.
American educational institutions have repeatedly conducted research to find out the network demand, and several basic plans for the next generation Internet initiative have been drawn up. These initiatives include the White House Next Generation Interent2 (NGI) initiative, the National Science Foundation (NSF) Ultra-high Bandwidth Network Service (VBNS), and the cooperation between universities, enterprises and governments. These actions will produce new protocols, new hardware, new software, new knowledge and new experimental networks to verify their capabilities.
1, Next Generation Internet (NGI)
The White House Next Generation Internet Initiative (NGI) is a multi-agency initiative announced by the US government in June 5438+0996 and June 5438+00. The research work of NGI mainly involves the protocol, development, deployment and application demonstration of high-end experimental network, and some of the work will be realized through Internet2 or VBNS.
Among all the initiatives, NGI is the most advanced, especially the first-level network (Class 1) invested by the Advanced Research Projects Agency of the US Department of Defense and the Department of Defense, which has carried out experiments on the adaptability of network technology. Some of these networks are not even associated with TCP/IP. A key goal of NGI is to develop and demonstrate two experimental networks, which are respectively 100 and 1000 times faster than the current Internet in end-to-end speed, namely1000 Mbps and 1Gbps.
The network services NGI will operate include transaction security and network management. Now the direction of efforts is to make full use of existing products and businesses, so that NGI can easily carry out research and cooperation with enterprises. By the autumn of 1997, more than 150 Silicon Valley companies had participated as partners.
2. Ultra-high bandwidth network services
Before NGI and Internet2, the National Science Foundation (NSF) is going to establish a private network, namely VBNS (Ultra-high Bandwidth Network Service), to provide the next generation network service for qualified research institutions and users in universities.
By the autumn of 1997, VBNS had an OC- 12 link of about 14000 miles, and also provided a switched virtual circuit. In the network, two nodes can directly transmit signals to the ATM switch of MCI, and carry out end-to-end transmission at the second layer. At these two points, the signal can directly pass through MCI network without any router.
MCI will use IPv6(TCP/IP version 6) for VBNS; ; Provide bandwidth reservation service, which requires high bandwidth in application and ensures low transmission loss or delay.
MCI plans to establish more than 65,438+000 domestic connection points and about 20 international connection points by the end of 65,438+0998, and further enhance VBNS by using source-based routing. By 2000, the backbone rate of VBNS will be upgraded to OC-48.
At the same time, the research activities related to VBNS have also achieved results. MCI has developed a monitoring function, which can check the IP traffic in high-speed transmission sources.
At the same time, VBNS will also become an integral part of NGI development plan, providing a test platform for new applications and new network technologies.
3. Internet 2
After the introduction of ultra-high bandwidth network service (VBNS), colleges and universities unanimously agreed to share network resources on the new generation Internet, so they formulated the Internet2 plan that was misunderstood by many people. People's misunderstanding is that although this plan will adopt a new generation of Internet technology, it is not to replace the existing Internet, nor is it to build another network for ordinary users.
1997 September Advanced Internet Development Cooperation Organization (UCAID) was established to manage Internet 2 and help other joint organizations.
Although both Internet2 and VBNS have their own independent tasks and are independent of NGI, they are also interrelated. At present, VBNS provides backbone services for the second generation Internet. Internet 2 and UCAID have also participated in some projects of NGI in the field of higher education. In fact, Internet2 is considered as the first goal of NGI project, which is to connect 100 first-class universities and develop the next generation network applications.
Internet 2 plan requires 1998 autumn actual operation test. The application of Internet2 will run through all aspects of colleges and universities, including project collaboration, digital library, research promotion and distance education.