WAN (Wide Area Network)

WANs are large-scale networks that can stretch over countries and even con­ti­nents. They don’t connect in­di­vid­ual routers but in­ter­con­nect other networks like LANs or MANs. WANs can be public or operated by companies in order to link different locations over long distances. But how is a WAN set up, how does it differ from other sorts of networks, and which tech­nolo­gies are used?

WAN is the ab­bre­vi­a­tion for Wide Area Network. These networks cover large ge­o­graph­i­cal regions and link different smaller networks like LANs (Local Area Networks) or MANs (Met­ro­pol­i­tan Area Networks) with one another. For this reason, they are only used in a pro­fes­sion­al context.

Public WANs are operated by internet providers so that their customers can access the internet. Private Wide Area Networks are primarily set up by companies in order to enable cloud services, for example, and connect the networks of different company locations.

Besides WANs, there are similar terms such as WLANs, LANs, and MANs. The tech­nolo­gies behind these networks are related to the Wide Area Network but refer to different struc­tures. LANs and MANs mainly differ from WANs in terms of size.

LAN stands for Local Area Network. It refers to the in­ter­con­nec­tion of multiple computers at a single location (company premises, house­holds, etc.) into a network, allowing the computers to exchange in­for­ma­tion or access another network. The data trans­mis­sion rate of LANs is far quicker compared to WANs, since the distances involved are much smaller.

MAN stands for Met­ro­pol­i­tan Area Network. The network is the bigger brother of the LAN and connects cities and met­ro­pol­i­tan regions over distances of up to 100 kilo­me­ters, but is still smaller than a WAN. MAN uses fiber optic tech­nol­o­gy in order to link multiple LANs with each other.

By contrast, a Wireless Local Area Network (WLAN) is actually a LAN that works without the use of cable con­nec­tions. Here, wireless com­mu­ni­ca­tions tech­nol­o­gy is used to allow the in­di­vid­ual computers to talk to each other or another network like the internet, for example. Like a LAN, a WLAN can therefore be connected to a MAN which may in turn be connected to a Wide Area Network.

Since whole networks rather than in­di­vid­ual computers are in­ter­con­nect­ed with a WAN, the tech­nol­o­gy used differs in com­par­i­son with other network types. Other trans­mis­sion protocols and address concepts are applied.

WANs use trans­mis­sion tech­nolo­gies and protocols in up to three layers as part of the OSI reference model. A WAN thereby works on a bit trans­mis­sion layer (layer 1), the security layer (layer 2), and the network layer (layer 3).

Wide Area Networks use a con­sis­tent address scheme, since un­ad­dressed data trans­mis­sion would be in­ef­fi­cient with the number of connected networks. In­ter­me­di­ate systems or network nodes like switches, bridges, and routers enable the data packets sent to be forwarded to the right address. Using hardware, data packets are sent from a sub­net­work to another and then delivered to the correct network par­tic­i­pant – which could be a PC, smart­phone, TV or even a smart fridge. The un­der­ly­ing tech­nol­o­gy is TCP/IP protocol stacks. The different protocols of this protocol family ensure that data is addressed correctly and reaches the right des­ti­na­tion even in the event of transport dif­fi­cul­ties, for example.

The following tech­nolo­gies are also used for data trans­mis­sion:

• X.25 (older tech­nol­o­gy, since the 1970s)
• Asyn­chro­nous Transfer Mode (ATM) (older tech­nol­o­gy)
• Mul­ti­pro­to­col Label Switching (IP/MPLS)
• Ple­siochro­nous Digital Hierarchy (PDH)
• Syn­chro­nous Digital Hierarchy (SDH)
• Ethernet

Copper and fiber optic cables as well as wireless con­nec­tions are used as physical trans­mis­sion media. Fiber optic cable is par­tic­u­lar­ly suitable for con­nec­tions over great distances of land and water. In­no­va­tions include satellite-supported broadband data trans­mis­sion, which can be set up rel­a­tive­ly quickly. In practice, a mixture of different trans­mis­sion media is typically used. The various types of cables can be connected with each other with the use of media con­ver­tors. At major internet nodes – special points of exchange – more than hundreds of networks are often in­ter­con­nect­ed to enable efficient data exchange. Repeaters ensure that data packets don’t lose any in­for­ma­tion as they travel across large distances.