What is LAN and a WAN Differences between a LAN and a WAN
Basic Networking

LAN and a WAN: Differences between a LAN and a WAN

In this article, I am going to tell you what is LAN and a WAN and also the difference between a LAN and a WAN so keep reading this article till the end.

Computers can be connected to form a network. On these networks, we can share data, resources, information, communicate with other people and computers. Two computers could be connected with each other. Similarly, tens or hundreds or thousands of computers could be connected in a variety of ways and scales to form a network. A network is a group of two or more computer systems sharing services and interacting in some manner. In a network, computers link physically and through software components to facilitate communication and the sharing of information.

In a network, a pathway known as the transmission medium connects the systems and a set of rules determines how they communicate. LAN (Local Area Network) and WAN (Wide Area networks) are just the ways computers could be connected and how their connections could be organized on a different scale.

What is a LAN?

A LAN is confined to a specific location, such as a floor, building, or some other small area. Being in a confined area, it means that in most cases it is possible to use only one transmission medium. This makes a LAN less expensive to implement and higher connection speeds could be obtained. Hence, LANs are used widely to connect personal computers and workstations in offices, department buildings, university hostels, factories, etc. places to share resources.

In a LAN, usually, all machines are attached to each other through the transmission medium. This is achieved by following different topologies for connection, such as the star, mesh, bus, etc. Traditional LANs run at the speed of 10 Mbps to 1000 Mbps. Since the computers are connected directly with each other in proximity, LANs have very low propagation delays as compared to WANs and the error rates are also very low. LANs are more secure than WANs or MANs.

LANs have private ownership. It is usually an organization, university or department that owns and operates the LAN. It has a very small area as compared to a MAN (Metropolitan Area Network) or a WAN.

What is WAN?

A Wide Area Network or a WAN covers a very large geographical area when compared to a LAN. This area can span an entire state, region, country, or even a continent. A WAN can be a connection of multiple LANs. Multiple connected LANs of different departments of the same organization can be called as a WAN. These departments, as a separate unit, can work independently as individual LANs, and at the same time, they can communicate and share resources with each other to form a part of the wider WAN.

WANs are wider and are hence usually not owned by a single private entity. Hence, WAN infrastructure is usually leased as a service from third-party service providers. These service providers include an ISP (internet service provider), Private IP network operator or cable company, a telecommunications carrier. Though, the WAN services itself might operate over a dedicated, private connection (having some sort of service-level agreement). The WAN services may also operate over a shared, public medium like the internet.

The internet over a particular region or a country can be called as an example of WAN. Hence, WANs are important from a national/information security point of view also.

The common problems associated with WANs are High setup cost, possible security gaps, need of robust anti-viruses and firewalls, etc.

The differences between LAN and WAN can become more clear from the following table:

Coverage Local areas only (e.g., library, offices, hostels) Larger geographic areas (e.g., cities, states, nations)
Speed High speed ( up to 1000 Mbps) Less speed ( up to 150 Mbps)
Data transfer rates LANs have a high data transfer rate, with lesser delays and errors. WANs have a lower data transfer rate compared to LANs. Delays and errors are more as compared to LANs.
Example The network in an research facility can be a LAN. The Internet which connects computers over a country – is a good example.
Technology Tend to use certain connectivity technologies, primarily Ethernet and Token Ring WANs tend to use technologies like MPLS, ATM, Frame Relay and X.25 for connectivity over longer distances
Connection One LAN can be connected to other LANs over any distance via telephone lines and radio waves. Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites.
Components Layer 2 devices like switches and bridges; Layer 1 devices like hubs and repeaters are used. Layers 3 devices Routers, Multi-layer Switches, and Technology specific devices like ATM or Frame-relay Switches, etc. are used.
Fault Tolerance Since the LANs are smaller and have lesser components, they tend to have fewer problems associated with them. Since WANs contains a large number of systems, they are less tolerant to faults.
Data Transmission Error Experiences fewer data transmission errors Experiences more data transmission errors as compared to LANs as the network is vast with many components.
Ownership Typically owned, controlled, and managed by a single person or organization. WANs (like the Internet) are not owned by anyone organization but rather exist under collective or distributed ownership and management over long distances.
Set-up costs Addition or repair of a few devices over a LAN incurs an incremental cost. It is not much expensive to do that. For WANs since networks in remote areas have to be connected, the set-up costs are higher. However, WANs using public networks can be set up very cheaply using just software (VPN, etc).
Geographical Spread Since they have a small geographical range, they don’t need any lease telecommunication lines. Since their spread is large, even across boundaries, they need leased communication lines.
Maintenance costs Due to shorter geographical coverage and fewer components, maintenance costs are lower. Because of its wider coverage area and multiplicity and complexity of components, maintenance costs are higher.
Bandwidth High bandwidth is available for transmission. Since, usually physical transmission medium is used in proximity for communication. Low bandwidth is available for transmission, as the network has a lot of components, and the bandwidth is hence shared.
Congestion Less congestion, because of a limited number of devices connected. More congestion, because of a lot of devices and routes connected to it.

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