LAN Computer Term

local area network (LAN)

  

Contributor(s): Diana Hwang

A local area network (LAN) is a group of computers and peripheral devices that share a common communications line or wireless link to a server within a distinct geographic area. A local area network may serve as few as two or three users in a home-office or several hundred users in a corporation’s central office. Home owners and information technology (IT) administrators set up LANs so that network nodes can share resources such as printers or network storage.

LAN networking requires cables, switches, routers and other components that let users connect to internal servers, websites and other LANs that belong to the same wide area network (WAN). Ethernet and Wi-Fi are the two primary ways to enable LAN connections. Ethernet is a specification that enables computers to communicate with each other. Wi-Fi uses radio waves to connect computers to the LAN.

Other LAN technologies, including Token Ring, fiber distributed data interface (FIDDI and ARCNET lost favor as Ethernet and Wi-Fi speeds increased and connectivity costs decreased.

Wireless Communication

The  wireless communication  or wireless is one in which the  communication ( transmitter / receiver ) is not attached by a propagation medium physical, but the used modulation of electromagnetic waves through space. In this sense, physical devices are only present in the transmitters and receivers of the signal, among which we find: antennas , laptops , PDAs , mobile phones , etc.           

Wireless network

The term  wireless network  (in English: wireless network) is used in computer science to designate the connection of nodes that occurs through electromagnetic waves, without the need for a   wired or wired network . Transmission and reception are done through ports.

History of the Wireless Network

Wireless communication, which is carried out through radio frequency waves  , facilitates operation in places where the computer is not in a fixed location (warehouses, multi-storey offices, etc.) is currently used in a general and accessible way to all public. It should also be mentioned that wired networks have an advantage in terms of data transmission over wireless networks. 

The practicality wins between WLAN and LAN

From a technical point of view, the LAN network exceeds the WLAN. Especially in terms of security, the cable network is clearly superior. It is also possible to interfere with WLAN wv Wifi signals in other ways, for example with the so-called Jammers, which cause the wireless connection to stop working. Creating fake WLAN networks is a common practice for hackers to obtain private data and passwords. These types of attacks are completely ineffective in LAN networks. An attacker would need physical access to the computer to enter the system. This makes the LAN extremely secure.

In addition to the security factor, a connection through the LAN is much faster. Instead, several devices connected to a single WLAN simultaneously can weaken and slow down this type of connection. Even structural elements such as concrete walls or swimming pools can disturb the connection of a WLAN. The great defect of the LAN is the lack of practicality and the disorder caused by the cables that must reach the device. In many cases, mobility and practicality of factors always prevail over safety and speed when preferring the wireless connection.

WHAT IS WIRELESS OR WIFI?

The meaning of WiFi or wireless is Wire (cable) Less (without), that is to say "without cables". Wireless is understood as transmissions or equipment capable of transmitting and / or receiving data without the need to be physically connected to each other.

An example of Wireless transmission is when we put on the headphones without cables and receive the sound of the television or when we change the channel with the remote control.

From the previous examples it can be deduced that there are or exist different types of Wireless since it cannot be the same to receive sound from a television than to connect to the Internet through a laptop, on the other hand the previous example will also help us to differentiate Wireless from WiFi , the WLAN definition headphones that give us the sound are not a WiFi device since they do not comply with the 802.11b / g / n standard.

We will differentiate the wireless transmissions from the WiFi although in a more global vision they can "be the same". From this differentiation we find the Wireless via infrared or IR that is commonly used in television controls and mobile phones. The Wireless that follows the IEEE standards and the 802.11a, b, g, n and the newest Wireless standards that is regulated by the IEEE but does not follow any 802.11x standards is the bluetooth that emits at the same frequency as the WiFi devicesbut its emission capacity and scope are smaller. Bluetooth is used for communications between mobiles and different devices with a relatively lower bandwidth need.

Maximum distance reached

The scope depends on many factors. Manufacturers talk about a range of 100 to 300 meters indoors. In open environments without obstacles and with direct line of sight, the range is considered in kilometers. The factors to consider are the types of antennas, the line of sight, the emission power and the curvature of the earth .

802.11 protocol

The 802.11 protocol or standard is responsible for setting the rules and conditions or defining the parameters so that a WiFi element can access the medium, transmit or receive information .

The 802.11 protocol uses air as a means of transmission at a free emission frequency . This frequency is 2.4GHz, some variants of the 802.11 protocol also use the frequency range of 5.4GHz . These two free frequencies are incapable of crossing walls and obstacles in general, so it is very difficult to obtain good coverage if you do not have a direct view of an emitting node within the network.

The fact that this free frequency is used does not mean that we are not subject to any regulations. Currently the regulations regulate the emission power that cannot exceed 100mW .

This protocol is also responsible for defining the way in which we will access this medium. Before being able to send any message, a series of actions that the sender must execute are marked so that when it transmits, no other node can do it. Technically these actions are known as CSMA / CA (Carrier Sense Multiple Access / Colision Avoidance).

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