On the basis of the area a network covers, it can be divided into the following types:

    *  LAN      -  Local Area Network
    *  WLAN  - Wireless Local Area Network
    *  MAN     - Metropolitan Area Network
    *  WAN     - Wide Area Network
    * SAN       -  Storage Area Network, System Area Network, Server Area Network, Small Area Network

    * CAN      - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
    * PAN      - Personal Area Network
    * DAN      - Desk Area Network


The original categories of computer networks were only LAN, MAN and WAN. The other categories evolved during the advancements in the technology of computer networks.

LAN (Local Area Network)

A LAN is a network of computers and devices over a relatively short geographical area. An office building networked with computers,a school or college or a home usually contains a single LAN, though sometimes one building will contain a few small LANs (probably one per room), and occasionally a LAN will span a group of nearby buildings. In addition to operating in a limited space, LANs are also controlled by a single person or organization. A LAN also tend to use certain connectivity technologies, primarily Ethernet or Token Ring.

 WAN - Wide Area Network
A WAN  spans a large physical distance compared to a LAN. The internet is the largest and the most common example of a WAN, that spans the whole Earth. A WAN can be considered as a collection of several LANs that are dispersed throughout the whole world. The network device Router connects several LANs to form the WAN. The Router also maintains both a LAN address and a WAN address in IP networking.

WLAN  - Wireless Local Area Network
WLAN is also a type of LAN(local area network) based on wireless network technology mostly referred as Wi-Fi. In contrast to a LAN, in WLAN no wires are used; radio signals are the medium for communication. To access any wireless network around, wireless network cards must be installed in the system. The wireless cards are connected to the Wireless Routers for the purpose of communication among the computers.