(Continued) After 1970s, the Advanced Research Projects Agency (DARPA, D) of the United States started a project called Internet to study how to connect packet-switched networks. From 65438 to 0974, WintonCerf and RobertKahn developed two basic protocols of the Internet-TCP and IP. IP is the abbreviation of InternetProtocol, which means Internet Protocol. Its function is to allow any number of computer networks to connect and run uniformly. TCP is the abbreviation of TransmissionControlProtocol, which means transmission control protocol. It is a communication protocol based on Internet protocol, which is used to distinguish and transmit data, and ensure that all data can reach the destination correctly and be reassembled. With TCP/IP, different networks can be easily connected into a larger network, and the information sent by any computer in the network will be delivered to the destination through an optimal route under the control of these protocols. The reason why DARPA calls this project the Internet, that is, the Internet or the Internet, is to find a way to connect the existing networks into a large network conveniently, so that this network will have great flexibility and almost unlimited scalability.

While ARPA is studying their Internet projects, many private companies are also building their own networks. Computer researchers have developed various LAN and WAN technologies, but they are incompatible with each other. At this time, an unexpected thing happened to most people, that is, DARPA unconditionally disclosed TCP/IP, which means that anyone in the world can freely use this technology to realize the interconnection between networks and establish the Internet. Many people are puzzled by the US military's unconditional disclosure of its advanced technology in the Cold War era. In fact, if you think about it carefully, you will understand that for any network, its value will be greater only if more nodes are connected. When a network becomes a completely open system, its value can be said to be endless, so the US military only made a wise decision from its own interests.

1979, mainly established by the Computer Science Research Network (CSNET) invested by the National Science Foundation of the United States. In 1980, vint cerf suggested that ARPANET and CSNET should use TCP/IP protocol to connect with each other through a gateway, and CSNET*** should enjoy the gateway of ARPANET to realize the interconnection of multiple networks. Gateway plays a role similar to translation intermediary, realizing free communication between networks using different communication protocols. We should not underestimate CERF's suggestion, because it directly led to the birth of the Internet. 1982, the prototype of the internet has been completed. Researchers can dial in CSNET and exchange emails with CSNET and ARPANET, and the Internet is officially put into use.

Since then, other agencies of the US government have also started to use the Internet and funded research on the Internet. The successful design of NSF (National Science Foundation) made it quickly replace ARPANET and become the backbone of the Internet.

At this time, many universities, non-governmental organizations and commercial organizations in different countries have established a large number of "networks", which are integrated into the Internet through different channels, laying a basic Internet model in which different small networks share large networks. As of 199 1, the Internet has developed too fast, and the backbone network of NSFNET can't meet the networking needs of more and more scientific research and education institutions. Because the Internet is an open network system, it is unreasonable to rely entirely on the US government to undertake the whole Internet, and the US government cannot afford it. So NSF asked private companies to take some responsibilities, so IBM, MCI and Merit formed an advanced network and service company, ANS (Advanced Network and Service). 1992, ANS built a new WAN, and the transmission line capacity was 30 times that of the original NSFNET backbone network. This is the current T3 Internet backbone ANSNET with a speed of 45Mbps. Because ANSNET is established by commercial organizations, it is significantly different from its predecessor, NSFNET, that is, the transmission lines and computers that make up NSFNET are owned by the federal government, while ANSNET is owned by ANS. Since 1988 allowed networks outside the United States to access NSFNET, most regions in the world have achieved direct connection with the Internet except a few countries and regions. It can be said that the endless Internet has really lived in the world.