Introduction to LANs, WANs, and Other Kinds of Area Networks

One way to categorize the different types of computer network designs is by the scope or scale of the network. For historical reasons, the networking industry refers to nearly every type of design as some type of area network.

Types of Area Networks

Common types of area networks are:

• LAN: Local Area Network
• WAN: Wide Area Network
• WLAN: Wireless Local Area Network
• MAN: Metropolitan Area Network
• SAN: Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network
• CAN: Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
• PAN: Personal Area Network

LAN and WAN are the two primary and best-known categories of area networks, while the others have emerged with technology advances.

LAN: Local Area Network

A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building contains a few small LANs (perhaps one per room), and occasionally a LAN spans a group of nearby buildings. In TCP/IP networking, a LAN is often, but not always, implemented as a single IP subnet.

In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. These networks also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.

WAN: Wide Area Network

A WAN spans a large physical distance. The internet is the largest WAN, spanning the Earth.

A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

A WAN differs from a LAN in several important ways. Most WANs (like the internet) aren't owned by a single organization. Instead, WANs exist under collective or distributed ownership and management.

WANs tend to use technology like ATM, Frame Relay, and X.25 for connectivity over the longer distances.

LAN, WAN, and Home Networking

Residences typically employ one LAN and connect to the internet WAN through an internet service provider (ISP) using a broadband modem. The ISP provides a WAN IP address to the modem, and all the computers on the home network use LAN IP addresses (also called private IP addresses).

All computers on a home LAN can communicate directly with each other but must go through a central network gateway, typically a broadband router, to reach the ISP and beyond.

Other Types of Area Networks

While LAN and WAN are the most popular network types, you may also see references to these others:

• Wireless Local Area Network: A LAN based on Wi-Fi wireless network technology.
• Metropolitan Area Network: A network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN is typically owned and operated by a single entity such as a government body or large corporation.
• Campus Area Network: A network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus.
• Personal Area Network: A network that surrounds an individual. A wireless PAN (WPAN) might be created between Bluetooth devices.
• Storage Area Network: Connects servers to data storage devices through technology like Fibre Channel.
• System Area Network (also called Cluster Area Network, or CAN): Links high-performance computers with high-speed connections in a cluster configuration.
• Passive Optical Local Area Network: A POLAN serves fiber by using fiber optic splitters to allow a single optical fiber to serve multiple devices.