Classification of Network by Geographical Coverage

Computer networks may be classified according to scale as follows: 

Personal Area Network (PAN)                                                                                                        

•      A Personal Area Network (PAN) is a computer network used for communication among computer devices close to one person. 

•      Some examples of devices that are used in a PAN are printers, fax machines, telephones, PDAs or scanners. 

•      The reach of a PAN is typically within about 20-30 feet (approximately 6-9 metres).

•      Personal area networks may be wired with computer buses such as USBand FireWire. 

•      A Wireless Personal Area Network (WPAN) can also be made possible with network technologies such as IrDA and Bluetooth.

Local Area Network (LAN)                                                                                                 

          

•      A network covering a small geographical area, like a home, office, or building is a LAN. 

•      Current LANs are most likely to be based on Ethernet technology. For example, a library may have a wired or wireless LAN for users to interconnect local devices (e.g., printers and servers) and to connect to the internet. 

Campus Area Network (CAN)                                                                                            

•      A network that connects two or more LANs but that is limited to a specific and contiguous geographical area such as a college campus, industrial complex, or a military base. 

•      A CAN may be considered a type of MAN (metropolitan area network), but is generally limited to an area that is smaller than a typical MAN. 

•      This term is most often used to discuss the implementation of networks for a contiguous area. This should not be confused with a Controller 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 will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet.

Metropolitan Area Network (MAN)                                                                                               

•A Metropolitan Area Network is a network that connects two or more Local Area Networks or Campus Area Networks together but does not extend beyond the boundaries of the immediate town/city. Routers, switches and hubs are connected to create a Metropolitan Area Network.

Wide Area Network (WAN)                                                                                                

          

•      A WAN is a data communications network that covers a relatively broad geographic area (i.e. one city to another and one country to another country) and that often uses transmission facilities provided by common carriers, such as telephone companies. 

•      WAN technologies generally function at the lower three layers of the OSI reference model:

the physical layer, the data link layer, and the network layer.

Global Area Network (GAN)                                                            

•      Global Area Networks (GAN) specifications are in development by several groups, and there is no common definition.

•      In general, however, a GAN is a model for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. 

•      The key challenge in mobile communications is "handing off" the user communications from one local coverage area to the next.