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Planning and Designing 802.11 Wireless Technologies

Contents

  1. Wireless Introduction
  2. WLAN Organizations and Regulations
  3. IEEE 802.11 Standards and Protocols

Chapter Description

On top of normal networking issues, WLAN adds a couple of new challenges, such as Layer 1 (radio frequency [RF]) issues; a set of L2 protocols, such as IEEE 802.11; and the need for agencies to regulate the use of this shared medium, as the authors explain in this excerpt from their book, CCIE Wireless Exam (350-050) Quick Reference.

IEEE 802.11 Standards and Protocols

802.11 Alphabet Soup

In June 1997, the IEEE finalized the initial standard for WLANs: IEEE 802.11. Each amendment has been published with a letter in addition to the 802.11. Those letters are often used to name features, data rates, and so on.

Here is a typical example: IEEE 802.11a defined operations in the 5-GHz band. The radio interface operating at 5 GHz is therefore called the “A radio.”

In 2007, the IEEE consolidated all amendments into a new 802.11 standard. Table 1-1 gives a summary of the standards in place at the time of this writing.

Table 1-1. IEEE 802.11 Standard Overview

Name

Description

Obsoleted By

802.11

Original standard defining 1- and 2-Mbps 2.4-GHz RF and IR. All the following are amendments to this standard.

802.11-2007

802.11a

This standard defines Orthogonal frequency-division multiplexing (OFDM) 54-Mbps operation in the 5-GHz band.

802.11-99

802.11b

Enhancements to 802.11 to support 5.5 Mbps and 11 Mbps in the 2.4-GHz band.

802.11-99

802.11c

Defi nes bridging operations for 802.11. 802.11c has been included as a chapter in the 802.1D standard concerning wireless bridging.

802.1D

802.11d

International roaming extensions. Adds a country fi eld in beacons and other frames. Adds countries not defi ned by the original standard.

802.11-2001

802.11e

Quality of service (QoS) features. Wi-Fi Multimedia (WMM) is a subset of 802.11e.

802.11-2007

802.11F

Set of recommendations (optional) defi ning the Inter-Access Point Protocol (IAPP) for exchanging client security context between access points (AP). This amendment was withdrawn in 2006.

802.11-2003

802.11g

Defines effective radiated power - OFDM (ERP-OFDM) modulation in 2.4 GHz, enabling 54 Mbps with backward compatibility with 802.11b.

802.11-2003

802.11h

Amendment for spectrum and transmit power management. It adds Dynamic Frequency Selection (DFS) to avoid radar in the 5-GHZ band as well as Transmit Power Control (TPC) to the 802.11a specifi cation.

802.11-2007

802.11i

Wi-Fi Protected Access (WPA) was an early subset of 802.11i, whereas Wi-Fi Protected Access 2 (WPA2) is the full 802.11i implementation. It defi nes Robust Security Network's (RSN), Advanced Encryption Standard (AES), and Temporal Key Integrity Protocol (TKIP) encryptions.

802.11-2007

802.11j (2004)

Amendment specific for regulation in Japan allowing use in the 4.9-GHz band.

802.11-2007

802.11-2007

Currently the latest revision of the standard, including amendments for 802.11a through 802.11j (except for .11c and .11F).

__

802.11k

Proposed amendment that defi nes radio management. It will facilitate roaming in an Extended Service Set (ESS) by helping to choose the best access point available (load balancing).

__

802.11l

Reserved and will not be used.

__

802.11m

An ongoing task group charged with the maintenance of the standard. It periodically produces the revisions as well as clarifi cations and modifi cations.

__

802.11n

Amendment unleashing high speeds, Multiple Input Multiple Output (MIMO), 40-MHz channels, and many other features.

__

802.11o

Reserved and will not be used.

__

802.11p

Defines WAVE (Wireless Access for Vehicular Environment) for ambulances and other high-speed vehicles and a roadside infrastructure in the licensed band of 5.9 GHz.

__

802.11q

Not used, to avoid confusion with 802.1q VLAN trunking.

__

802.11r

This amendment is charged with ensuring fast roaming, even for vehicles in motion. It is supposed to reduce the roaming delay between two basic service sets (BSS) to less than 50 ms.

__

802.11s

This amendment will standardize mesh networks.

__

802.11T

This amendment regroups recommended practices to test and measure performance in wireless networks. Also called WPP (Wireless Performance Prediction).

__

802.11u

Proposed amendment to improve internetworking with external non-802.11 networks. The idea is to be able to specify services provided by a BSS, to allow access to the BSS depending on previous authentication with other networks, and to restrict access to the BSS.

__

802.11v

This amendment will enable confi guring clients while they are connected to the network.

__

802.11w

This amendment will bring protected management frames. It is supposed to be an add-on to 802.11i covering management frame security.

__

802.11x

Not used to avoid confusion with 802.1x.

__

802.11y

Allows operation in the 3650- to 3700-MHz band (licensed), allowing higher power and thus longer ranges.

__

802.11z

Direct Link Setup (DLS) allows two stations to communicate directly with each other.

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