What is a LAN?

A local area network (LAN) consists of two or more computers connected together in a building or home using software and hardware. This is contrasted to a wide area network (WAN) such as the Internet, which covers a large geographic area. In a LAN, there is a main computer or server, and remote computers called clients. By creating this type of network in the home or office, computers on it can share files, resources, and if desired, an Internet connection.

A LAN can be one of two types: wired or wireless. A wired LAN requires Ethernet cable to physically connect all computers on the network to a main device called a switch. The wireless type uses radio waves to communicate, eliminating the need for wires. Therefore, the hardware used in the network should all be of either the wireless or wired type.

A LAN is fairly easy to setup. All Microsoft operating systems since Windows 98 Special Edition (SE) have included built-in networking software. In terms of hardware, each computer requires a network interface card (NIC). A switch is also required. This is a device that resembles an external modem and directs information on the network. If the LAN will be talking to another network, like the Internet, a router is also required. Luckily, one can purchase an external DSL modem with a built-in switch and router, in wireless or wired configurations.

Desktop computers typically use internal NICs that slip into an available slot on the motherboard, while a laptop might use a portable computer (PC) NIC. This type of NIC resembles a thick credit card that can be inserted into the PC card slot on the laptop.

If the LAN is to be hard-wired, each NIC must have an Ethernet port for connecting an Ethernet cable. In a wireless LAN, each NIC might feature a small radio wave antenna. The server is hard-wired to the DSL modem, switch or router, while the clients can communicate wirelessly, if desired. If there is to be no connection to the Internet or any other network, a switch alone will be fine.
Once the local area network has been set up, an administrator can designate which files and programs can be shared on it. Some areas of the server may be kept behind a firewall to prevent access. All traffic on the network, including email, Internet surfing and other activities, can be monitored by the administrator using various tools.
The advantages of a LAN in the office are manifold. By having a central printer, for example, a business can avoid buying individual printers for each workstation. Workflow is enhanced while being easier than ever to control and administer. Flexibility and creativity can also improve. It is often a win-win situation for management and employees alike.
A LAN at home is extremely convenient. Share programs, images, music and digital projects, and enjoy gaming. Share a high-end color printer, scanner or other equipment. If concerned about your children’s Internet use, this is one way to supervise online activity.
A hard-wired LAN is more trouble to install, as it requires running a physical Ethernet cable from each client to the DSL, switch or router. However, this type is reliable and secure. A wireless LAN is easier to install and less expensive, but requires a few more steps in the software setup to ensure it is secure. It may also be slower than wired, but this depends on the wireless standard used, as newer standards effectively compete with Ethernet speeds.