Local Area Network (LAN)
The smallest office network is referred to as a local area network (LAN). A LAN is formed from computers and components in a single office or building.
Home Area Networks (HAN)
A home area network is really no different from a LAN. It often uses the same hardware components as a LAN, but a HAN is mainly used to share Internet access.
Wide area networks.
LANs in different locations can be connected by high-speed fiber-optic, satellite, or leased phone lines to form a wide area network (WAN).
The Internet.
The World Wide Web is the most visible part of the world's largest network, the Internet. The Internet is really a network of networks, all of which are connected to each other through the TCP/IP protocol. Programs such as web browsers, File Transfer Protocol (FTP) clients, and email clients are some of the most common ways users work with the Internet.
Intranets.
Intranets use the same web browsers and other software and the same TCP/IP protocol as the public Internet, but intranets exist as a portion of a company's private network. Unlike the Internet, the content is restricted to authorized company users only. An intranet is a private Internet.
Extranets.
Intranets that share a portion of their content with customers, suppliers, or other businesses, but not with the general public, are called extranets. As with intranets, the same web browsers and other software are used to access the content.
VPN:
This uses the public telephone line to create a virtual private network among users.
