[Literature Review]

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Table of Contents

BACKGROUND3

QUALITY OF SERVICE (QOS)10

DISTRIBUTED COORDINATION FUNCTION (DCF)13

RELATED WORK19

Main IEEE 802.1121

ARCHITECTURAL OVERVIEW22

SUMMARY23

Literature Review

Background

The 802.11 standard is actually the first standard and allows a bandwidth of 1 to 2 Mbps The original standard has been modified to optimize the bandwidth (including 802.11a, 802.11b and 802.11g physical standards called 802.11) or to specify components best way to ensure greater security and compatibility. (Draves 2004 14-16) The table below shows the different modifications of the 802.11 standard and their meanings:

Name of standard

Name

Description

802.11a

Wifi5

The 802.11 standard (called WiFi 5) supports a higher bandwidth (maximum total throughput is 54 Mbps but in practice is 30 Mbps). The 802.11a standard provides eight radio channels in the frequency band 5 GHz

802.11b

Wifi

The 802.11 standard is the most commonly used. It offers a maximum throughput of 11 Mbps (6 Mbps in practice) and has a range of 300 meters in open space. It uses the frequency range of 2.4 GHz with three available radio channels.

802.11c

Combination of 802.11 and 802.1d

802.11c The combined standard of no interest to the general public. It's just a modified version of the standard that combines 802.1d 802.1d compatible devices 802.11 (in the data link layer).

802.11d

Internationalization

The 802.11d standard is a supplement to the 802.11 standard is designed to enable international use of the local 802.11 networks. Allows multiple devices to exchange information in the frequency ranges as allowed in the country of origin of the device.

802.11e

Improved service quality

The 802.11e standard is intended to improve the quality of service at the level of the data link layer. The standard's goal is to define the different packages requirements in terms of bandwidth and transmission delay to allow better audio and video transmissions.

802.11f

Roaming

The 802.11f is a recommendation for access point vendors that allows products to be more compatible. Use the IAPP protocol that allows a roaming user clearly changed an access point to another while moving no matter what brands of access points used in the network infrastructure. Also this property is known simply as roaming.

802.11g

The 802.11g standard provides high bandwidth (with a maximum throughput of 54 Mbps 30 Mbps but in practice) in the frequency range 2.4 GHz 802.11g standard is compatible with the previous standard, the 802.11b, which means that devices that support the 802.11g standard can also work with 802.11b.

802.11h

The 802.11h standard is intended to unite the 802.11 standard with the European standard (HiperLAN 2, hence the h in 802.11h) and comply with European regulations concerning the use of frequencies and energy efficiency.

802.11i

The 802.11i standard is intended to improve security in data transfer (to manage and distribute keys, and to implement encryption and authentication). This standard is based on AES (Advanced Encryption Standard) and can encrypt transmissions technologies running on 802.11a, 802.11b and 802.11g.

802.11Ir

802.11r The standard was developed so you can use infrared signals. This standard has become technologically obsolete.

802.11j

The ...