What's a LAN (Local Area Network)?

An introduction to the essential concepts of a LAN

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

Multiple local networks may stand alone, disconnected from any other network, or might connect to other LANs or a WAN (like the internet). Traditional home networks are individual LANs but it is possible to have multiple LANs within a home, like if a guest network is set up.

Technologies Used to Build a LAN

Modern local area networks predominantly use either Wi-Fi or Ethernet to connect their devices together.

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 through Ethernet cables.

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

Though Ethernet and Wi-Fi are usually used in most businesses and homes, due both to the low cost and speed requirement, a LAN may be setup with fiber if enough reason can be found.

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.

Note: Other types of area networks may be larger than LANs, like MANs and CANs.

Benefits of a Local Area Network

There are plenty of advantages to LANs. The most obvious one, like mentioned above, is that software (plus licenses), files, and hardware can be shared with all the devices that connect to the LAN. This not only makes things easier but it also reduces the cost of having to buy multiples.

For example, a business can avoid having to buy a printer for each employee and computer by setting up a LAN to share the printer over the whole network, which lets more than just one person print to it, fax things, scan documents, etc.

Since sharing is a major role of a local area network, it's clear that this type of network means faster communication. Not only can files and other data be shared much quicker if they stay within the local network instead of reaching the internet first, but point-to-point communication can be setup for quicker communication.

Also on this note, sharing resources on a network means there's central administrative control, which means it's easier to make changes, monitor, update, troubleshoot, and maintain those resources.

LAN Topologies

A 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. However, the average user of a computer network does not need to know much about them.

Bus, ring, and star topologies are the three basic forms that are known by most networking-literate people.

What Is a LAN Party?

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 with the benefit of high-speed, low-latency connections to support real-time game types.