LAN (Local Area Network)

Local Area Networks not only provide the necessary con­nec­tion between gamers’ computers at LAN parties. They’re now also used in many house­holds, where multiple digital end devices need to access the internet or home printer. But what exactly is a LAN, how is it different from other types of networks and which tech­no­lo­gies does it involve?

LAN is the ab­bre­vi­ation for Local Area Network. It refers to networks within a limited area. LANs are typically used in private house­holds or in companies to set up home or corporate networks. This allows the various devices to com­mu­nic­ate with each other.

A LAN comprises at least two end devices, but it can also link several thousand devices to one another. If larger distances need to be bridged, however, this is normally achieved using MANs and WANs. A Local Area Network can connect computers, smart­phones, printers, scanners, storage devices, servers and other network devices with each other and to the internet. If a printer is only connected to a computer via a USB cable, for example, usually only this PC will be able to access the device. But con­nect­ing the printer to the network allows multiple devices in the area to use the printer.

Other terms also crop up in the context of LANs: WANs, WLANs, and MANs may sound similar, but they refer to different types of networks. WLAN stands for Wireless Local Area Network and is also known in­ter­na­tion­ally as Wi-Fi. Here, computers are connected by wireless com­mu­nic­a­tion. This is not the case with MANs and WANs. These networks only differ from a LAN in terms of size.

WAN stands for Wide Area Network. This kind of network connects in­di­vidu­al LANs or MANs even over large distances. A WAN can cover entire countries or con­tin­ents. By contrast, a MAN is a Met­ro­pol­it­an Area Network. This type of network is the LAN’s big brother, con­nect­ing devices within a city or met­ro­pol­it­an region. MANs mostly use fibre optic tech­no­logy to connect multiple LANs. A MAN can encompass up to 100 kilo­metres.

Nowadays, virtually all LANs are realized via Ethernet. In the past, LANs were also im­ple­men­ted using the following tech­no­lo­gies which nowadays hardly play a role anymore:

• Token Ring
• DECNET
• FDDI (still used in some cases to connect Ethernet and Token Ring tech­no­logy)
• ARCNET (outdated but still used in in­dus­tri­al auto­ma­tion)

Ethernet achieves data trans­mis­sion rates of up to several hundred Gbits/s. The tech­no­logy uses either twisted pair cable or – the newer method – fibre optic cable. While con­ven­tion­al copper cables can only bridge up to 100 meters, fibre optic cables can stretch over several miles. In order to ensure that the data actually arrives via the cable con­nec­tions and that data packets don’t block each other, tech­no­logy such as CSMA/CD is used. In the case of a WLAN in which data packets are trans­mit­ted wire­lessly, CSMA/CA is utilised.

An Ethernet LAN can be divided into multiple virtual LANs (VLANs) or physical LANs. The virtual structure enables ad­min­is­trat­ors to partition networks without needing to implement major in­fra­struc­ture changes.

Switches and routers are used to organise Local Area Networks. The hardware acts as an interface and governs the con­nec­tions between the in­di­vidu­al network par­ti­cipants, ensuring the data packets reach their des­tin­a­tion. Also, when data is trans­mit­ted from a LAN to the internet or in­form­a­tion is to be accessed from other networks or data centres, the con­nec­tion occurs via a router. By contrast, repeaters and hubs which pre­vi­ously performed similar tasks are scarcely used in modern LANs.

Network cables, network sockets, and network patches are also used as physical com­pon­ents when setting up a LAN. They connect the in­di­vidu­al end devices and servers with each other and offer network ad­min­is­trat­ors and home admins the ability to neatly install the network in the office or at home.