Connecting one computer to another computer creates a network.

A computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport.

A computer network that connects two or more LANs and usually covers a larger geographic area.

Wired Wireless Combination

The Internet, also referred to as the Net, is a worldwide system of networked computers that uses a common set of rules that enable collaboration, communication, and commerce.

Need for a system that could survive major losses In 1962, the United States had several research facilities around the country that used computers. The government wanted to speed up research by connecting the labs so their computers could exchange data. In 1968, The Advanced Research Projects Agency (ARPA), created a small network called ARPANET.

In 1982, a new method was created to allow messages to be sent on multiple pathways. The data is divided into small packages that is transmitted independently and reassembled at the destination. The rules used to manage data exchange are called protocols. Protocols are standards that allow networks to communicate even if they use equipment from different manufacturers.

The two major protocols for transmitting packets across the network are referred to together as Transmission Control Protocol/Internet Protocol(TCP/IP). For example, if you send a file to a friend’s computer TCP/IP breaks the file into several packets and labels each packet with the Internet address of your friend’s computer. Since these packets will travel separate routes, some arriving sooner than others, TCP/IP assigns a sequence number to each of the packets. These numbers will be used by the TCP/IP on your friend’s computer to reassemble the packets. This complicated process of TCP/IP takes place in a matter of milliseconds.

Regardless of its physical location, each computer connected to the Internet has a unique address called its IP address. IP stands for Internet Protocol. An IP address is a number that uniquely identifies each computer connected to the Internet to other computers connected to the Internet, for the purpose of communication and transfer of data packets. IP address are grouped as a series of four sets of numbers separated by dots, such as

An addressing system was devised that could provide each resource on the Internet with a unique address. The system is called the Uniform Resource Locator (URL).

A domain name is the part of the text-based URL that identifies the company or organization that owns the Web site. Because a domain name may be used only once throughout the entire world an organization called Internet Corporation for Assigned Names and Numbers (ICANN) oversees the registration of new domain names and administers IP addresses.

In 1989, Tim Berners-Lee, a computer programmer, developed a way for computers to share text documents. The documents were placed on computers that acted as servers, and other computers were able to run programs called clients that could retrieve and display the documents. Berners-Lee used a browser – a program that requests and displays Web pages – to display documents. He named his browser WorldWideWeb and made it available for free to anyone on the Internet that wanted to use it.

In 1992, Marc Andreessen and several other students at the University of Illinois took Berners-Lee’s browser and added the ability to embed graphical elements. They called their browser Mosaic. It was available as a free download on the Internet and by 1993 more than one million people were using it. Today the three most common Web browsers are Internet Explorer, Firefox, and Safari.

Web browser programs use Hypertext Markup Language, or HTML to describe how text and figures should be displayed. A document that is written in HTML and displayed by a browser is a Web page. The method used to transfer Web pages is called HTTP or Hypertext transfer protocol. Web pages contain links to other web pages, which are called hyperlinks. The links are typically identified with a different color font and underlining.

A company or organization that sells the service of its gateway is called an Internet Service Provider (ISP). Types of ISPs Dial-Up Telephone Service – slow speed technology that uses telephone lines DSL Telephone Service – high speed technology that uses telephone lines Cable television Service – high speed technology that uses coaxial cable and sometimes fiber optic cables Laptop Connect Card – a device that uses a cellular network to connect to the Internet.

Internet Usage Statistics Internet Growth Statistics

Older video explaining the Web World Wide Web in Plain English