The Internet is a global network of computers that works just like the postal system, only at speeds up to one second per second. Just as the postal service allows people to send each other envelopes containing messages, the Internet enables computers to send each other small packets of digital data.
To do this, they use a common “language” called TCP/IP (Transmission Control Protocol/Internet Protocol). If you are online, you have an IP address.
How the Internet works
When you send a letter, you don’t need to know about the vans, trains and planes that carry it to its destination, or how many post offices it passes on the way. Nor do you need to know how your Internet data packets are transmitted through the various cables, routers and host computers on the way to their destination.
How the Internet works
However, different packets can take different routes, which makes the Internet relatively resilient. The failure of a particular node or host usually means little or no difference to the rest of the system.
If you put a letter in an envelope, it can contain many different types of data: a love letter, an invoice, a photograph, etc. Internet data packets also carry different types of data for different applications. Common types include web pages, email messages and large files, which can be digital videos, music files or computer programs.
Today, the Internet is often used to provide an easy-to-use interface for numerous applications, including e-mail, file transfer, Usenet newsgroups, and messaging (Internet relay chat). This makes the web(network) and the Internet look similar. However, these (network) applications existed before the invention of the Internet and can still work without it.
The Internet originated from ARPAnet, created by the US Department of Defense’s Advanced Research Projects Agency in the 1960s. Many other networks were developed – some by commercial companies, some in different countries – but they could not easily communicate with each other.
Vint Cerf and Bob Kahn developed TCP/IP, the “Packet Network Interconnection Protocol” (1974) to connect the different networks. The Internet was thus a “network of networks”. The Internet Protocol (IP) became dominant in networking.
At the end of 1969, there were only four computers on the ARPAnet, and they were all in US universities. Their number grew to 5000 Internet hosts in 1986, after which the number of users quickly grew into the millions and then hundreds of millions.
No wonder the Internet is included in the list of inventions that changed the world. The main reasons for this massive growth were the opening of the existing academic and government network to commercial users and its rapid spread from the US to the rest of the world.
Allied factors were the huge growth of the personal computer market in the 1980s, Tim Berners-Lee’s invention of the World Wide Web in the early 1990s, and the widespread adoption of broadband in the 2000s.