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1. The evolution of computer networks
The origin of the Internet (a product of the Cold War)
In a sense, the Internet can be said to be a product of the Cold War between the United States and the Soviet Union. Its origins can be traced back to the early 1960s. At that time, the US Department of Defense believed that it was necessary to design a decentralized command system in order to ensure that the US homeland defense forces and overseas defense forces still had a certain ability to survive and counterattack after the first nuclear strike by the former Soviet Union; it is composed of scattered command points. When some of the command points are destroyed, other points can still work normally, and between these points can bypass those that have been destroyed and continue to maintain contact.
Appaent (Arpanet)
In 1969, the United States Department of Defense Defense Advanced Research Program (DOD/DARPA) funded the creation of a network called **ARPANET (or Arpanet )**, which brought together the Universities of California, Los Angeles, and St.The computer mainframes of Barbara's University of California, Stanford University, and Utah State University in Salt Lake City are connected, and the large computers at each node use packet switching technology to communicate with each other through special communication switches and special communication lines. connect. The Arpanet is the earliest prototype of the Internet.
Small text files (E-mail) can be sent between each network, and large text files can be sent using the file transfer protocol.
A letter of agreement
It is mainly responsible for establishing a standard specification that can ensure communication between computers. That is the communication protocol!!!
TCP/IP protocol
- TCP (Transmission Control Protocol) and IP (Internet Protocol) are collectively referred to as the TCP/IP protocols.
- These two protocols define a method of transferring messages (files and commands) between computer networks.
- The TCP/IP protocol has also greatly promoted the development of computer networks.
- Each network uses its own communication protocol and uses the TCP/IP protocol when communicating with other networks.
- Attachment: The five-layer model of TCP/IP; each layer corresponds to a different network protocol.
2. The development stage of computer networks
Phase 1 (Remote Terminal Connection)
- The host is the network center and controller, and terminals (keyboards, monitors, etc.) are distributed in various places to connect with the host. Users use the host remotely through the terminal.
- The second stage (computer network-local area network)
- Multiple hosts are interconnected to realize the communication between computers. End users can access the hardware and software resources of the local host and all hosts on the communication subnet.
- The third stage (computer network interconnection-wide area network)
- Formulated by the International Organization for Standardization (ISO): The basic reference model for open system interconnection (OSI/RM), which realizes interconnection between computers produced by different manufacturers, The birth of the TCP/IP protocol
- The fourth stage (information high-speed-multi-service, large data volume)
- Broadband integrated services, ATM technology, online TV on demand, online shopping, online banking, etc.
Summary
The Internet is a great milestone in the development of human history. It is the prototype of the future information superhighway. Through it, human beings are entering an unprecedented information society. People call the Internet by various names, such as the international Internet network, the Internet of Things, the Internet, the interactive network, the Internet, etc. It is extending and spreading to all continents around 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 most abundant information resources in the world.
