# Computer networks

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This is a lesson in the course Introduction to Computers, which is a part of The School of Computer Science

## Definition of network

Providing an ability in a specified place and time, is called "Network". In better conditions, they provide an ability everywhere and at all times and its ideals:
* provide " everything " in " everywhere " and " every time ".
The abilities of water networks, electric networks, road networks, communication networks and treatment networks respectively are "water", "electricity", "relocation", "sound", etc. In computer science this ability in computer networks is data. The locations access to the ability in network is called a "Node".

## Why were networks created?

A "network" allows connected computers to share information and hardware. Imagine a business where there are many computers and a single printer. In this instance, the "network" allows each of the connected computers to access the printer at the same time, without changing the printer cable or moving it from computer to computer.
A "network" also allows connected computers to share files and data as well as hardware resources, i.e., scanners, plotters, projectors and storage devices, making it easier to collect and dispense information, and giving users the ability to collaborate.
The reason your computer has access to the material you are now reading is the result of "file-sharing" via the WIKIVERSITY network.
Different types of computer networks exist to serve different needs; Personal area network (PAN), Local area network (LAN), Metropolitan area network (MAN), Campus area network (CAN), Storage area network (SAN) and Wide area network (WAN).
The internet is a "network" as well, and clearly the largest and most complex of all.

## Types of common networks
### LAN

A local area network (LAN) is created by a group of computers that are in close proximity to each other, hence local. The computers typically connect to each other by way of a switch, which is a device that directs signals within the LAN. A wireless network is a LAN that is created using WiFi(a wireless technology) access point instead of wired ones. A LAN is typically created at schools and businesses that have an exclusive network for students and employees. A WiFi hotspot, like the ones found at Starbucks, would also be a LAN.

### WAN

A wide area network connects multiple LANs across large physical distances. They're commonly created by leasing a wire from a cable company or internet provider, although WAN typically doesn't require the internet in order to work. If the LAN of one school was connected to a LAN at a school in another state, the two together would be a WAN. A router is used to connect LANs.

### The Internet

The internet (Integrated Networks) is a special collection of networks all interlinked together. It is made up of networks called ISPs that interconnect the smaller LANs and WANs around it. There are multiple ISPs across the world, and all of these are connected, to create a global network of networks.

### VPN

Virtual private networks provide a special way to create a WAN by using the internet to connect LANs together, without leasing a private cable. An example might be if you were at your house, away from school; you can create a VPN to connect to the schools network, without having to lease a communications cable. A VPN encapsulates your data so that it is secure while traversing the internet.

## See Also

* Computer Networks
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