What is the real difference between LAN and WAN?

Question

What I understand is:

• A LAN is connecting two or more computers to form a cable network between them.
• A WAN is connecting two or more computers over a broad area to form a cable network between them.

So, is the difference the length of cable used to form a network or does it depend if it's formed in a city, state or between countries?

Answer 1

While LAN and WAN are both two branches of networking and share many similarities, there’s a very fine line between them as well

There are differences on the basis of scope and connections. When I was doing my Cisco qualifications I seem to recall that a WAN was typically over a large geographical area, like a huge private network (mini internet [intranet])

http://www.computer-realm.net/lan-wan/

• Difference on the basis of scope: WAN is considered to be more vast and widespread. WAN is meant for networking between wide geographical regions like between two cities or even across different time zones while LAN is mainly used for private connectivity among residential offices or a single edifice. Hence a small scale WAN can be developed by creating many LANs.

• Difference on the basis of connections: In case of LAN, Ethernet is the main device which is used for connecting the workstations or the computers. Ethernet is a bus based protocol device in which cables and wires and permanent. Ethernet helps is the interconnection of the different types of LANs. While in the case of WAN, common carriers are usually used and most people opt in for service providers. When it comes to the speed of both the network technologies, a LAN is usually faster as it is confined to a small space with servers in a nearby location.

Answer 2

Many Answers here have given textbook-like definitions that have touched on this, but there are certain practical, real-world distinctions worth underscoring:

A LAN is typically something completely within your own premises (your organization's campus, or building, or office suite, or your home), so it's something you build and own yourself, all the way down to the physical cabling. In contrast, a WAN is something that connects between geographically separated locations, so you generally have to lease access to lines or data transmission services from telecommunications carriers to create your WAN.

Because of the shorter distances needed for on-premises networks, and because of the focus on connecting PCs and servers, LANs tend to be built on Ethernet and other 802.3-family (and 802.11-family) physical layers and data links. 1000BASE-T, 1000BASE-SX, 1000BASE-LX, etc.

Because off-premises network links usually need to go longer distances and work over the telecommunication carriers' existing infrastructure, they tend to use physical and data-link standards that are more common in the telecom industry. Then again, for your convenience, telecom carriers usually hand off to you using an 802.3-family link, even if what they're using behind the scenes is, say, OC-3 and SONET/SDH.

Because of the technical hurdles associated with moving lots of data long distances reliably, WAN links tend to be lower bandwidth and higher latency than LAN links. Also, because you're usually paying a separate telecom carrier for the service, to keep costs down, most organizations try to limit (or at least not go crazy with) how much data they move over WAN links.

The differences between LANs and WANs tend to be at the physical and data-link layers. At the network layer (Layer 3 in the old-but-still-helpful-for-some-discussions OSI layering model), most people use IP (Internet Protocol) nowadays. Because it all uses IP, applications that use IP don't have to know what physical and data-link layers are in use, so anything you can do on a LAN you can potentially do on a WAN as well, if you have high enough bandwidth and low enough latency for whatever it is you're trying to do, and as long as you haven't blocked it at your firewall (or via the accidentally firewall-like properties of a NAT).

Answer 3

Networks are often classified by their physical or organizational extent or their purpose. Usage, trust level, and access rights differ between these types of networks.

Computer network types by area:

Body (BAN)
Personal (PAN)
Near-me (NAN)
Local (LAN)
    Home (HAN)
    Storage (SAN)
Campus (CAN)
Backbone
Metropolitan (MAN)
Wide (WAN)
Global (GAN)
Internet
Interplanetary Internet

LAN: A local area network (LAN) is a computer network that connects computers and devices in a limited geographical area such as home, school, computer laboratory or office building.

WAN: A wide area network (WAN) is a telecommunication network that covers a broad area (i.e., any network that links across metropolitan, regional, or national boundaries).

Answer 4

The confusion stems from the fact that networking has evolved greatly since the ARPANET. In the past, yes, location and distance was the predominant factor in the distinction between LAN and WAN, however today, it is both blurred, and somewhat re-defined. Today, the distinction is more in terms of addressing and administration, particularly for “LAN”.

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A LAN no longer needs to be in a single location. Yes, a home, school, or company-network is considered a LAN, but the term also applies to ISPs. That is, your ISP may provide Internet access to thousands of houses across a large city, and it is still considered a LAN (for example, consider warnings of how someone using the same ISP may be able to sniff your traffic because they are on the same network). In this case, the addresses of the systems on the network are confide to the IPs that the ISP owns and the network is administered by the same entity (the ISP).

A WAN on the other hand is usually defined more closely to what it was in the past: a disparate networks connected to each other. In this regard, your home-network connected to my home-network forms a WAN, even if they are both on the same ISP. In this case, each sub-network in the WAN is administered by a different entity (you and me), and likely has different addressing (your router may use different addresses, network masks, etc. than mine).

Another definition for a WAN that falls in line with what it used to be does in fact use the location. For example, a company can have a LAN in their office building, but when it connects to their LAN in another building in another city/country, it forms a WAN.

It’s sort of a matter of perspective; two small LANs form a small WAN, which itself is a LAN that connects to other small LANs which form a larger WAN, and so on.

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Another distinction for LAN and WAN that is easy to remember is the makeup of the networks. A LAN is usually just individual systems/devices connected to each other, while a WAN is usually networks connected to each other. That is, you don’t usually have a sub-network in a LAN, and you don’t usually have a single computer attached to a WAN all by itself.

Also, the networking hardware usually plays a role in the distinction, for example routers in LANs and switches in WANs; CAT5 cables and little wireless antennae for LANs and giant under-sea cables and satellites in orbit for WANs.

Answer 5

Here's a description of some of the differences...

• LAN LAN (Local Area Network) is a computer network covering a small geographic area. Home, office, or schools ar typical examples.

  WAN WAN (Wide Area Network) is a computer network that covers a broad area and whose communications links cross over other WANs. Metropolitan, regional, national and international networks are an example.

• LAN Usually uses networking technologies like Ethernet.

  WAN Uses technologies like Frame Relay or X.25

• LAN Typically runs across user-owned network infrastructure. Cables, modems, computers, routers.

  WAN Typically run across leased lines, and expensive equipment (like satellites, communications towers and communications centres) and ownership may be distributed among several organizations.

• LAN Typically offers high data transfers rates with good quality cables and small distances between endpoints.

  WAN Usually slower transfer rates. Distances usually impact on data transfer rates even if these are equal to LAN (10/100/1000 Mbps). Latency is much more visible in WANs due to the distances sometimes involved and the number of devices (or hops) a data packet has to travel through.

• LAN Cheap to setup and maintain.

  WAN Expensive to setup and maintain. Only at the reach of large communication corporations and governments.

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In addition there's also MAN (Metropolitan Area Network). These are usually smaller than WANs and larger than LANs (although there's really no size restrictions). Their purpose is to provide higher quality service or differentiated service to a smaller geographical area like a town, city, or university campus and to establish a connection between the several LANs it may serve and the WAN it may be served with.

Answer 6

One way to think about the difference is not in terms of size or geographical location, but control:

• A LAN is a network under the control and/or jurisdiction of a single entity;
• The WAN is everything else.

Your company may have routers in Chicago and LA, but since they're under one company's control, they're part of one LAN. You probably route traffic between them publicly, over the WAN.

Answer 7

A LAN is a group of computers in a single location or group (i.e. a school or a business).

A WAN is typically multiple networks connected in multiple locations.