Local Area Network (LAN)
A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building and has its network equipment and interconnects locally managed. By contrast, a wide area network (WAN), not only covers a larger geographic distance, but also generally involves leased telecommunication circuits or Internet links.
Ethernet and Wi-Fi are the two most common transmission technologies in use for local area networks. Historical technologies include ARCNET, Token ring, and AppleTalk.
What is a Local-Area Network (LAN)?
A local-area network (LAN) is a computer network that spans a relatively small area. Most often, a LAN is confined to a single room, building or group of buildings, however, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide-area network (WAN).
Nodes on a LAN
Most LANs connect workstations and personal computers. Each node (individual computer ) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending email or engaging in chat sessions.
LANs are capable of transmitting data at very fast rates, much faster than data can be transmitted over a telephone line; but the distances are limited and there is also a limit on the number of computers that can be attached to a single LAN.
Types of Local-Area Networks (LANs)
There are many different types of LANs, with Ethernets being the most common for PCs. Most Apple Macintosh networks are based on Apple's AppleTalk network system, which is built into Macintosh computers.
The following characteristics differentiate one LAN from another:
- topology : The geometric arrangement of devices on the network. For example, devices can be arranged in a ring or in a straight line.
A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link to a server. Typically, a LAN encompasses computers and peripherals connected to a server within a small geographic area such as an office building or home. Computers and other mobile devices can share resources such as a printer or network storage.
Usually, the server has applications and data storage that are shared in common by multiple computer users.
A local area network may serve as few as two or three users (for example, in a home network) or as many hundreds of users. Ethernet and Wi-Fi are the two most commonly used LAN technologies. Other LAN technologies, including Token Ring, Fiber Distributed Data Interface and ARCNET have lost favor as Ethernet and Wi-Fi speeds have increased. The rise of virtualization has fueled the development of virtual LANs (VLANs) which allows network administrators to logically group network nodes and partition their networks without the need for major infrastructure changes.
Typically, a suite of application programs can be kept on the LAN server. Users who need an application frequently can download it once and then run it from their local device. Users can order printing and other services as needed through applications run on the LAN server. A user can share files with others stored on the LAN server; read and write access is maintained by a network administrator. A LAN server may also be used as a Web server if safeguards are taken to secure internal applications and data from outside access.
In some situations, a wireless LAN, or Wi-Fi, may be preferable to a wired LAN because of its flexibility and cost. Companies are assessing WLANs as a replacement for their wired infrastructures as the number of smartphones, tablets and other mobile devices proliferates.