LAN - Local Area Network

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local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. LANs are built to enable sharing of resources - like files, printers, games or other applications - and services - like email or Internet access. 

Each of these local networks may stand alone (disconnected from any other network) or may connect to other LANs and additionally a WAN (such as the Internet).

Traditional home networks are individual LANs, although it is also possible to have multiple LANs within a home (such as in homes that set up a guest network).

Technologies Used to Build a LAN

Modern local area networks predominately use either Wi-Fi or Ethernet for connectivity among devices.

A traditional Wi-Fi LAN operates one or more wireless access points that devices within signal range connect to. These access points in turn manage network traffic flowing to and from the local devices and can also interface the local network with outside networks. On a home LAN, wireless broadband routers perform the functions of an access point.

A traditional Ethernet LAN consists of one or more hubs, switches, or traditional routers that individual devices connect to via Ethernet cables.

Both Wi-Fi and Ethernet also allow devices to connect to each other directly ("peer to peer" or "ad hoc" connections) rather than through a central device, although the functionality of these networks is limited.

Internet Protocol (IP) is by far the predominant choice of network protocol used on LANs. All popular network operating systems have built-in support for the required TCP/IP technology.

How Big is a LAN?

A local network can contain anywhere from one or two devices up to many thousands. Some devices like servers and printers stay permanently associated with the LAN while mobile devices like laptop computers and phones may join and leave the network at various times.

Both the technologies used to build a LAN and also its purpose determine its physical size. Wi-Fi local networks, for example, tend to be sized according to the coverage area of individual access points, whereas Ethernet networks tend to span the distances that individual Ethernet cables can cover. In both cases, though, LANs can be extended to cover much larger distances if needed by aggregating together multiple access points or switches.

LAN Topologies

computer network topology is the underlying communication structure for components of a LAN. Those who design network technologies consider topologies, and understanding them gives some additional insight into how networks work, but otherwise the average user of a computer network does not need to think about them much. Bus, ring and star topologies are the three basic forms well known to networking students.

What is a LAN Party?

The term LAN party refers to a type of multiplayer computer gaming and social event where participants bring their own computers and build a temporary local network. Before cloud-based game services and Internet gaming matured, LAN parties were essential for bringing together players for matchmaking and with sufficiently high-speed, low-latency connections to support real-time game types.

More: Introduction to LANs, WANs, and Other Types of Computer Networks