A computer network is an interconnection of a group of computers while Internet is a worldwide system of interconnected networks and computers.
History of Internet:
In 1969, Advanced Research Project Agency (ARPA) established a small computer network among different universities and defense organizations. ARPANet was the world’s first operational network that was developed to survive a nuclear attack. The goal was to establish a large computer network connecting a small number of users. There were only four hosts (A host is a computer that provide services to other computers of the network). But the network grew rapidly and spanned over countries.
Meanwhile another research organization, National Science Foundation, joined the project. NSF established five super computing centers, which were available to all researchers for academic purposes. To provide high-speed access to its supercomputers, NSF established a separate high-speed network called NSF net. During this period, some other small networks had also been established among various universities and organizations. The authorities decided to link ARPANet, NSFnet and other small networks so that they can communicate each other. This link among different networks is referred to as the Internet.
“The network of networks around the whole world is called Internet.” OR “Internet can be defined as a huge collection of millions of computers, all linked together on a computer network. This is a global network that allows all of the computers to communicate with one another”. Due to this network all computers can communicate with each other.
How the Internet Works?
A home computer may be linked to the Internet using a phone – line ISP. A computer in a business or university will usually have a network interface card (NIC) that directly connects it to a Local Area Network (LAN) inside the business. The business can then connect its LAN to an ISP using a high speed phone line like a T1 line. A T1 line can handle approximately 1.5 million bits per second, while a normal phone line using a modern can typically handle 30,000 to 50,000 bits per second. ISPs then connect to larger ISPs, and the largest ISPs maintain fiber – optic backbones” for an entire region. Backbones around the world are connected through fiber-optic lines, undersea cables or satellite links. In this way, every computer on the internet is connected to every other computer on the Internet. Internet is a data communication system. Through this system millions of computers in the world have linked together. In only one second several thousands of bytes travel on the Internet. This extremely large network of computer networks combines all the three major methods of communications i.e
- Earth-based telephone lines (WAN system)
- Sea-based Fiberglass cables (Submarine cables)
- Ether based satellite communications systems (Cyber Space)
The internet is not a real entity or a place that has building or a place. Instead, it is the result of a collaborative effort of people and computers throughout the world. The end result is an electronic link to the world of information and entertainment. In simply words, the Internet is a network of connected computers that provide us a facility of exchange data, messages, and files with other computers that are connected to the Internet. The Internet has grown rapidly since 1990. To understand how the Internet works, we need to have sufficient knowledge of “Networking” i.e. the connection of different computers in network.