Definitions

The purpose of this lesson is to introduce what the Internet and World Wide Web are, and how they fit into the world of computers and communication.

What Exactly is the Internet?

The Internet is best characterized as "the biggest network of computer networks on earth."

A computer network is a data communications system made up of hardware and software that transmits data from one computer to another. In part, a computer network includes physical infrastructure like wires, cables, fiber optic lines, undersea cables, and satellites. The other part of a network is the software to keep it running. Computer networks can connect to other computer networks to get an even bigger computer network.

The Internet is a set of connected computer networks.

From the Free Online Dictionary of Computing, we get this definition from its entry for Internet:

"The Internet is the largest internet (with a small "i") in the world."

We then get this definition from its entry for internet:

"Any set of networks interconnected with routers. The Internet is the biggest example of an internet. "

We then get this definition from its entry for router:

"A device which forwards packets between networks. The forwarding decision is based on network layer information and routing tables, often constructed by routing protocols."

While this might seem like too terse or technical of an answer, it is technically correct. An internet (small i) is simply a set networks connected by devices that exchange data with each other in packets. The Internet is the name given to the largest set of interconnected internets in the world. In particular, the method by which this data is exchanged on the Internet is through the TCP/IP protocol suite.

You can keep the difference between "Internet" and "internet" straight by remembering this: When you say "internet," you must always identify which internet you mean--there are millions and millions of internets in the world. However, when you say "Internet," you've said it all--there is precisely one and only one Internet in the universe.

Useful Tools

You can use a "traceroute" service to look at how data flows over the Internet along various paths. Look in the "Information/Utilities/Use via Web" section of the Internet Tools Summary for a link to Web-based visual traceroute sites.

You can also look at major players in global and regional networks connected to the Internet using the Mapnet Web site.

The Internet is not run by any one organization nor operated by any single agency. This makes a definition of the Internet that identifies a single organization who owns it or runs it impossible. In truth, the Internet is run by a vast patchwork of telecommunications organizations, research centers, universities, and private individuals through their mutual cooperation to ensure the exchange of data amoung their networks in packets using a common TCP/IP protocol.

Read over this presentation about the Internet to get more ideas about what the Internet is and how it works.

What is the World Wide Web?

From the Free Online Dictionary of Computing, we get this definition from its entry for WWW:

"An Internet client-server hypertext distributed information retrieval system."

The Web is not a network. The Web is not the Internet itself. The Web is not a proprietary system like AOL. Instead the Web is a system of clients (Web browsers) and servers that uses the Internet for its data exchange.

Exercise: Define the Internet and Web

If someone stopped you in the street and demanded to know your definition of the Internet and World Wide Web, what would you say? Define the Internet in your own words. How is the Web different from the Internet? How is the Internet and Web different from AOL?