Computer Network Management

Internetworking is connecting two or more distinct computer networks or the network segments via a common routing technology. The result is an internetwork often called internet.

Any interconnection among or between public,private, commercial, industrial, or governmental networks may also be defined as an internetwork.

In modern practice there are three variants of internetwork, depending on who administers and who participates in them:

* Intranet

* Extranet

* Internet

Intranets and extranets may or may not have connections to the Internet. If connected to the Internet, the intranet or extranet is normally protected from being accessed from the Internet without proper authorization.

# The Intranet

An intranet is a set of networks, using the Internet Protocol and IP-based tools such as web browsers and file transfer applications, that is under the control of a single administrative entity. That administrative entity closes the intranet to all but specific, authorized users.

Most commonly, an intranet is the internal network of an organization. A large intranet will typically have at least one web server to provide users with organizational information.

# The Extranet

An extranet is a network or internetwork that is limited in scope to a single organization or entity but which also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities.

Technically, an extranet may also be categorized as a CAN, MAN, WAN, or other type of network, although, by definition, an extranet cannot consist of a single LAN; it must have at least one connection with an external network.

# The Internet

The Internet is a specific internetwork. It consists of a worldwide interconnection of governmental, academic, public, and private networks based upon the networking technologies of the Internet Protocol Suite.

It is the successor of the Advanced Research Projects Agency Network (ARPANET) developed by DARPA of the U.S. Department of Defense.

The Internet is also the communications backbone underlying the World Wide Web (WWW).