LAN, WAN, MAN, PAN, What?
Probably the most common type of network, a LAN, or Local Area Network, is comprised of a collection of devices (mainly computers) that are connected to one another electrically. This means these devices can receive each other's electrical signals over common collection of wires, cables, or even wirelessly. Computers in a LAN are usually physically connected to the network at all times (although they might not be turned-on all the time).
A WAN, or Wide Area Network, is a collection of LANs connected together, allowing computers separated by large distances to still exchange data. While WANs do share much of the same networking hardware used by LANs, there is a difference between the two. WANs have some unique hardware and protocols that are tailored to exchanging of large amounts of data at high speeds over long distances.
A MAN, or Metropolitan Area Network, falls somewhere between a LAN and WAN, and is defined in geographical terms. A MAN may cover a city, group of buildings, or less commonly a larger area. In today's world, MANs mainly serve as community networks that provide shared services, such as a wireless internet connection, to the local community or educational institution.
While the distinction between LAN, MAN, and WAN is useful in understanding the purpose of such networks, one cannot distinguish between them by solely looking at the technology that is being used to create one or the other. LANs, MANs, or WANs use similar technology and concepts, and the distinction mainly exists in how they are used.
An emerging type of network is the PAN, or Personal Area Network. A PAN is a wireless connection between devices that are relatively close together for the purpose of eliminating wiring. For example, a PAN could be used to allow a computer to use a printer without needing to physically plug-in a printer cable from one device to the other. Or a PAN could allow a user to listen to a portable music player without a cable between the player and the headphones. The PAN is differentiated from a wireless LAN because the maximum distance between devices in a PAN is only a few meters whereas in a wireless LAN devices may be over a hundred meters apart. Bluetooth technology is becoming the most common PAN technology, allowing cables between devices, such as a mouse, keyboard, or printer, to be replaced wirelessly. Today, there are a wide range of Bluetooth enabled devices available, including mice, keyboards, printers, headphones, and more. However, adoption of Bluetooth is not as widespread as other wireless networking technologies.