A Brief History of Computer Networks

The development of computer networks has come a long way. The various communication software we use today undoubtedly relies on computer networks. But do you know the background of the emergence of computer networks? We have eliminated the phenomenon of information silos now, but several years ago, did you know that computer networks could help us connect the world and eliminate information silos? Let’s talk about the development process of computer networks.

The Birth of the Internet

In 1946, the first computer in the world was born, but at that time there was no computer network, so computers could only work independently. Even if two computers were very close, they could only be like introverted children, keeping to their own corners.

After World War II, the US and the Soviet Union were competing for supremacy. For military purposes, the US established a secret department called ARPA, which aimed to develop a decentralized command system at the request of the US Department of Defense. This system would have many nodes, and even if some nodes were destroyed, the other nodes could still communicate with each other. This project was completed in 1966, and ARPA named it ARPANET. ARPANET was one of the earliest computer networks and is considered the predecessor of the Internet.

ARPANET was one of the first computer networks to use packet switching. Data communicated through the packet-switching system would be formatted into data packets with target machine addresses, which would then be sent over the network to be received by the next machine.

The term data packet was coined by Donald Davies in 1965 to describe the data transmitted between computers over a network. Data packets play a crucial role in computer networks and can be said to be the protagonists of the Internet.

ARPANET was officially launched in 1969. Also in 1969, Steve Crocker from UCLA published the first RFC paper, which is considered the beginning of the Internet. In the same year, the first network switch achieved the first data transmission on ARPANET, marking the official birth of the Internet.

We often reference .rfc at the end of an article or communicate with someone who presents a vague idea, and when you ask him further, he tells you to check the RFC document (as if he was talking about me). A more official explanation of RFC is that it describes the methods, behaviors, research, or innovations of the Internet and Internet systems.

In simpler terms, it is the official documentation of Internet protocols.

The Birth of TCP/IP

Although communication was possible between a few nodes, the number of nodes was still quite limited, only four. Moreover, ARPANET had many limitations, such as the inability to communicate between different computer networks. To solve this problem, ARPA launched a new research project to interconnect different local area networks.

The early ARPANET used a network protocol called NCP, but with the development of the network and the increasing user demand for network access, the NCP protocol could no longer adequately support the development needs of ARPANET. Furthermore, NCP had a significant flaw: it could only be used in the same operating system environment, meaning that Windows users could not communicate with MacOS or Android users.

Therefore, ARPANET urgently needed a new protocol to replace the outdated NCP protocol. The responsibility fell to Robert E. Kahn and Vinton G. Cerf, two legendary figures whose theories are unprecedented even today. What did these two professors do? I will just briefly mention: they proposed a new transmission control protocol—TCP (Transmission Control Protocol). Many people refer to Robert E. Kahn and Vinton G. Cerf as the fathers of the Internet. In 1974, they published a paper titled “A Protocol for Packet Network Communication” in the IEEE journal, officially proposing TCP/IP to achieve interconnection between computer networks.

Although we consider the TCP/IP protocol a great invention, it was not well-received at the time. Moreover, the four-layer model of TCP/IP seemed relatively simple compared to the seven-layer model proposed by ISO. However, hard work pays off. After four years of continuous improvement, the TCP/IP protocol finally completed its foundational infrastructure. In 1983, the US Department of Defense Advanced Research Projects Agency decided to eliminate the NCP protocol and replace it with the TCP/IP protocol. It took a full ten years from the paper’s proposal to its adoption. In 1985, TCP/IP became part of the UNIX operating system. Subsequently, almost all operating systems gradually began to support TCP/IP, and this protocol became mainstream.

Further Development

In the early 1980s, ARPANET achieved great success, but universities that did not have contracts with federal agencies could not use it. To solve this problem, the National Science Foundation (NSF) began to establish a Computer Science Network (CSNet) for university students. CSNet was a protocol layer added on top of other basic networks, using the communication capabilities provided by other networks. From the user’s perspective, it was also an independent network. CSNet adopted a centralized control method, with all information exchanges passing through a single repeater.

In 1986, the NSF invested in establishing supercomputer centers at five universities, forming NSFNET. Due to the encouragement and funding from the NSF, many universities, government agencies, and even private research institutions began to connect their local area networks to NSFNET. From 1986 to 1991, the number of subnets in NSFNET rapidly increased from 100 to over 3000.

Not only did schools join, but many academic organizations, enterprises, research institutions, and even individuals also became users. The users of the Internet were no longer limited to pure computer professionals. New users found that communication between computers was more appealing to them. They gradually began to use the Internet as a tool for communication and interaction, rather than just sharing the computing power of NSF’s giant computers.

The Internet is a collection of global information, composed of countless subnets, each containing several computers.

By the early 1990s, the Internet already had many subnets, each responsible for its own setup and operating costs. These subnets were interconnected through NSFNET, which connected millions of computers across the United States and had tens of millions of users, becoming the main member network of the Internet. As computer networks expanded globally, networks outside the US gradually connected to the NSFNET backbone or its subnets.

1993 was a crucial year in the development of the Internet, as it saw the completion of all major technological innovations to date. The application of WWW – the World Wide Web and browsers created a refreshing platform on the Internet: the content seen on the Internet was no longer just text, but included images, sound, animations, and even movies. The Internet evolved into a new world where text, images, sounds, animations, and films intermingled at an unprecedented speed, sweeping the globe.

The rapid rise of the Internet attracted worldwide attention, and China also placed great importance on the construction of information infrastructure, emphasizing connectivity with the Internet. The information networks that have been built and are under construction have a profound impact on China’s technology, economy, and social development, as well as on information exchange with the international community.

The Development of the Internet in China

Although the start of the Internet in China was not as early as in the US, China has the fastest Internet growth rate in the world.

The development of the Internet in China originated from 1987 to 1993, during which domestic scientists began to access Internet resources. During this period, a group of research institutes, led by the Institute of High Energy Physics of the Chinese Academy of Sciences, collaborated with foreign institutions on research projects related to Internet connectivity. They used dial-up methods to access the Internet’s E-mail system and provided international Internet email services for some key universities and research institutions in China.

In October 1990, China officially registered the highest domain name cn with the International Internet Information Center, thereby opening up the use of its own domain for Internet email.

In January 1994, the National Science Foundation of the US accepted China’s formal request to connect to the Internet. In March 1994, China was approved to join the Internet. In early April, at the Sino-US Science and Technology Cooperation Joint Committee, the Chinese government officially requested to connect to the Internet and received approval. Thus, China finally opened the last link, marking full contact with the Internet on April 20, when the NCFC project connected to the international Internet dedicated line. By May of the same year, China’s networking work was fully completed, and the Chinese government recognized the entry of the Internet into China. The domain name for China’s network was eventually determined to be cn. This event was rated as one of the top ten science and technology news stories in China in 1994 and listed as one of the major scientific achievements of China in 1994 by the National Statistical Bulletin.

Since 1994, China has achieved TCP/IP connectivity with the Internet, gradually opening up full functional services of the Internet; large-scale computer network projects were officially launched, marking the beginning of a rapid development period for the Internet in China. In 1995, China Telecom established dedicated lines in Beijing and Shanghai, providing Internet access services to society through telephone lines, DDN dedicated lines, and X.25 networks. In May 1995, the CHINANET national backbone network began to be constructed, and in January 1996, the CHINANET backbone network was completed and officially opened, marking the start of public computer interconnection services nationwide, indicating a rapid development phase for the Internet in China.

China has successively built several nationwide public computer networks, the largest of which are:

• China Telecom Internet CHINANET
• China Unicom Internet UNINET
• China Mobile Internet CMNET
• China Education and Research Network CERNET
• China Science and Technology Network CSTNET

It can be seen that the construction of the Internet in China can be divided into three stages:

• The first stage is from 1987 to 1993, known as the enlightenment stage or experimental stage, during which China began to access the Internet and conducted research projects and scientific cooperation. However, the network applications during this stage were limited to small-scale email services.
• The second stage is from 1994 to 1996, known as the startup stage or deployment stage, during which China began to construct backbone networks and connect to the Internet, officially recognized as a country with Internet access. Subsequently, several Internet network projects, such as ChinaNet, CERNET, and CSTNET, were launched nationwide.
• The third stage is from 1997 to the present, which focuses on nationwide access to the Internet, marking a rapid development phase for the Internet in China.

Entering the 21st century, the CERNET2 experimental network was launched, connecting three core CERNET nodes in Beijing, Shanghai, and Guangzhou at speeds of 2.5 Gbit/s – 10 Gbit/s, marking that China’s Internet has reached an internationally advanced level.

The CNNIC (China Internet Network Information Center) publishes information on the development of the Internet in China every year. Interested parties can find relevant information at www.cnnic.cn.