The Internet is a worldwide collection of interconnected networks (internetworks or internet for short). The figure shows one way to view the Internet as a collection of interconnected LANs and WANs. Some of the LAN examples are connected to each other through a WAN connection. WANs are then connected to each other. The red WAN connection lines represent all the varieties of ways we connect networks. WANs can connect through copper wires, fiber optic cables, and wireless transmissions (not shown).
The Internet is not owned by any individual or group. Ensuring effective communication across this diverse infrastructure requires the application of consistent and commonly recognized technologies and standards as well as the cooperation of many network administration agencies. There are organizations that have been developed for the purpose of helping to maintain structure and standardization of Internet protocols and processes. These organizations include the Internet Engineering Task Force (IETF), Internet Corporation for Assigned Names and Numbers (ICANN), and the Internet Architecture Board (IAB), plus many others.
Note: The term internet (with a lower case “i”) is used to describe multiple networks interconnected. When referring to the global system of interconnected computer networks or the World Wide Web, the term Internet (with a capital “I”) is used.
[Intranets and Extranets]
There are two other terms which are similar to the term Internet:
Intranet is a term often used to refer to a private connection of LANs and WANs that belongs to an organization, and is designed to be accessible only by the organization’s members, employees, or others with authorization.
An organization may use an extranet to provide secure and safe access to individuals who work for a different organization, but require access to the organization’s data. Examples of extranets include:
A company that is providing access to outside suppliers and contractors.
A hospital that is providing a booking system to doctors so they can make appointments for their patients.
A local office of education that is providing budget and personnel information to the schools in its district.