© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—2-1 111 © 2003, Cisco Systems, Inc. All rights reserved

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—2-1111© 2003, Cisco Systems, Inc. All rights reserved.

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—2-2

Module 2

IEEE 802.11 and Network Interface Cards


Learning Objectives

•Identify the IEEE 802. standards.

• Identify the IEEE 802.11 standards.

•Understand the MAC and PHY layers of 802.11

•Identify which client operating systems are supported.

•Determine the status of a client card by observing the indicator lights.

•Install and configure a Cisco Aironet PC Card.


Overview

This chapter will cover the IEEE 802.11 WLAN (WLAN) standards in detail, including data link and physical layer specifications. Throughout this module and this course, the terms IEEE and 802 are used often. This module provides a short overview of IEEE and the 802 committee. The MAC and physical layer services that have been standardized will be discussed. Finally, client adapters, driver types, and client support will also be discussed.


Key terms

• IEEE

• MAC

• PHY

• NIC

• STA

• MSDU

• PLCP

• PMD

• BSS


802.11 Standards


IEEE 802.11 Standards Activities

802.11a: 5GHz, 54Mbps

802.11b: 2.4GHz, 11Mbps

802.11d: Multiple regulatory domains

802.11e: Quality of Service (QoS)

802.11f: Inter-Access Point Protocol (IAPP)

802.11g: 2.4GHz, 54Mbps

802.11h: Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC)

802.11i: Security

802.11j: Japan 5GHz Channels (4.9-5.1 GHz)

802.11k: Measurement

802.11m: Maintenance

802.11n: High-Speed


802.11a / 5 GHz Band

Data rates supported: 54, 48, 36, 24, 12, and 6 Mbps•Client will automatically “downshift” to lower data rate when it gets further from AP

23 Countries have approved the use of 802.11a products:•U.S. Australia Austria Denmark France Sweden New ZealandIreland Japan Singapore TaiwanArgentina•U.K. Germany Norway Portugal Canada Belgium NetherlandsFinland Poland Switzerland Mexico

802.11h will ultimately permit worldwide usage of WLANs @ 5 GHz•Transmit Power Control (TPC)•Dynamic Frequency Selection (DFS)

5.470-5.725 GHz band being opened up (11 more channels)•This new 5.47-5.725 GHz band, plus 5.25-5.35 GHz UNII-2 band, will require DFS•Current UNII-2 products in the market will likely be grandfathered (i.e. no DFS)

5 GHz band has more channels than 2.4 GHz band•UNII-1 + UNII-2 = 8 channels (plus 11 future channels) vs. 3 channels for 2.4 GHz•However, depending on distance between AP’s, you may only be able to use half of the 5 GHz channels due to adjacent channel interference

5 GHz band subject to less interference than 2.4 GHz band•However, 2.4 GHz interference not a major problem in most business environments


Three Wireless Technologies

The Laws of Radio Dynamics:Higher Data Rates = Shorter Transmission RangeHigher Power Output = Increased Range, but Lower Battery LifeHigher Frequency Radios = Higher Data Rates Shorter Ranges

802.11b 802.11a 802.11g

2.4 GHz 5 GHz 2.4 GHz

Worldwide US/AP Worldwide

11 Mbps 54 Mbps 54 Mbps

FrequencyBand

Availability

MaximumData rate

Other Services(Interference)

Cordless Phones Microwave Ovens Wireless Video Bluetooth Devices

Cordless Phones Microwave Ovens Wireless Video Bluetooth Devices

HyperLAN Devices


IEEE 802.11 Standard

IEEE 802.11 became a standard in July 1997• 2.4 GHz at 2 Mbps Frequency Hopping Spread Spectrum

(FHSS) and Direct Sequence Spread Spectrum (DSSS)

IEEE 802.11a and 802.11b became standards in September 1999• 802.11a – 5 GHz at 54 Mbps OFDM

• 802.11b – 2.4 GHz at 11 Mbps DSSS

IEEE 802.11g is scheduled to be ratified in 2003

• 802.11g – 2.4 GHz at 54 Mbps OFDM

802.11 promises “true” vendor interoperability


Standards and Organizations


WLAN Speeds & Frequencies

802.11g2.4 GHz – OFDM/CCK

54 Mbps

Proprietary IEEE 802.11a/b Ratified

802.11a5 GHz – OFDM

54 Mbps

802.11b2.4 GHz – CCK

11 Mbps

Jan’99 Jan’00 Jan’01 Jan’02 Jan’03 Jan’04


What Is WLAN RF Technology?

Data sent over the air waves

Two-way radio communications (half duplex)

Same radio frequency for sending & receiving (transceiver)

No licensing required for Cisco Aironet Wireless products (in most countries)


IEEE 802. Standards


802.11 Architecture


802.11 Physical (PHY) Layer Modulations


Stations (STA)


PHY Protocols


Basic Service Set (BSS)


Independent Basic Service Set (IBSS)


Extended Service Set (ESS) and Distributed System (DS)


MAC Layer


MAC Services


MAC Architecture


CSMA


Interframe Spaces


PHY Layer


PHY Functions


802.11b


2.4 GHz Channel Sets

Americas Americas Europe, Middle East and AsiaEurope, Middle East and Asia

1

2

3

4

5

6

7

8

9

10

11

12

13

14

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Center Frequency

Center Frequency

2412 MHz

2417 MHz

2422 MHz

2427 MHz

2432 MHz

2437 MHz

2442 MHz

2447 MHz

2452 MHz

2457 MHz

2462 MHz

2467 MHz

2472 MHz

2484 MHz

2412 MHz

2417 MHz

2422 MHz

2427 MHz

2432 MHz

2437 MHz

2442 MHz

2447 MHz

2452 MHz

2457 MHz

2462 MHz

2467 MHz

2472 MHz

2484 MHz

JapanJapan IsraelIsrael

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Regulatory DomainRegulatory DomainChannel IdentifierChannel Identifier


Channels- 2.4 GHz DSSS

11 “chips per bit” means each bit sent redundantly

11 Mbps data rate

3 access points can occupy same area

11 Channels – each channel 22 MHz wide

1 set of 3 non-overlapping channels

14 Channels – each channel 22 MHz wide

4 sets of 3 non-overlapping channels, only one set used at a time


802.11b Access Point Coverage

1 Mbps DSSS

5.5 Mbps DSSS

11 Mbps DSSS

2 Mbps DSSS


802.11b Scalability

Blue = 11 Mbps

Green = 11 Mbps

Red = 11 Mbps

Total Theoretical Bandwidth = 33 Mbps


Comparing the Technologies802.11a Data Rates

Modulation with Sub Channels

Modulation with Sub Channels

BPSKBPSK

Data Rate Per Subchannel

(Kbps)

Data Rate Per Subchannel

(Kbps)

BPSKBPSK

QPSKQPSK

125125

187.5187.5

250250

QPSKQPSK 375375

Total Data Rate (Mbps)

Total Data Rate (Mbps)

66

99

1212

1818

16QAM16QAM

16QAM16QAM

64QAM64QAM

500500

750750

10001000

64QAM64QAM 11251125

2424

3636

4848

5454


802.11a Channel Sets

Am

eric

as (

-A)

Jap

an (

-J)

Sin

gap

ore

(-S

)

Tai

wan

(-T

)

34 5170 x36 5180 x x38 5190 x40 5200 x x42 5210 x44 5220 x x46 5230 x48 5240 x x52 5260 x x56 5280 x x60 5300 x x64 5320 x x

40 40 20 40

Channel Set

Cisco Maximum Peak Power (mW)*

Channel IDFrequency

(MHz)

Americas include:

Argentina

Australia

Austria

Brazil

Canada

Chile

Columbia

Denmark

France

Mexico

New Zealand

Panama

Peru

Sweden

United Kingdom

United States

Venezuela


802.11a Access Point Coverage

OFDMOFDM54 Mbps54 Mbps

48 Mbps48 Mbps

36 Mbps36 Mbps

24 Mbps24 Mbps

18 Mbps18 Mbps

12 Mbps12 Mbps

09 Mbps09 Mbps

06 Mbps06 Mbps


802.11a Scalability (Indoor UNII-1 and 2)

54 Mbps

54 Mbps

54 Mbps

Total Theoretical Bandwidth = 432 Mbps8 non-overlapping channels

54 Mbps

54 Mbps

54 Mbps

54 Mbps

54 Mbps


Client Adapters


Cisco Aironet 802.11b Client Adapters

2.4 GHz• 802.11b

• 11 Mbps

Include• PC Card

• PCI Card

• LMC Card

• Mini PCI


802.11b PC Card

2.4 GHz/802.11b• 11 Mbps

Rate Shifting • 1, 2, 5.5, and 11Mbps

Fixed data rates • User configurable option

Integrated Antenna

PCMCIA interface

Transmit power settings:• 100 mW, 50 mW, 30 mW, 20 mW,

10 mW, 5 mW, and 1 mW


802.11b LMC Card

2.4 GHz/802.11b• 11 Mbps



PCMCIA interface

Transmit power settings:• 100 mW, 50 mW, 30 mW, 20

mW, 10 mW, 5 mW, and 1 mW


802.11b PCI Card

2.4 GHz/802.11b• 11 Mbps



RP-TNC Connector

PCMCIA interface

Transmit power settings:• 100 mW, 50 mW, 30 mW, 20 mW,

10 mW, 5 mW, and 1 mW


802.11b Mini PCI Adapter

2.4 GHz/802.11b embedded wireless for notebooks

100 mW transmit power

Must order through PC manufactures (not orderable directly through Cisco)


802.11a CardBus2 Client Adapter

5 GHz/802.11a• 54 Mbps

Rate Shifting • 6, 9, 12, 18, 24, 36, 48, or 54


5 dBi Patch Antenna

CardBus interface

Transmit power settings:• 20 mW, 10 mW, and 5 mW


PC Card LEDs

Dual LED helps identify the card status

• Green LED is the Status LED

• Orange LED is the RF traffic LED


LED Status


Windows Drivers


Linux and Macintosh Drivers


Downloading Drivers and Software


Ad-Hoc


Infrastructure


Aironet Client Utility: Main Screen


Aironet Client Utility: Loading Firmware


Aironet Client Utility: Profile Manager


Aironet Client Utility: Adding a Profile


Profile: System Parameters


Profile: RF Network


Profile: RF Network


Profile: Advanced (Infrastructure)


Profile: Advanced (Ad Hoc)


Profile: Network Security


Aironet Client Utility: Status


Aironet Client Utility: Statistics


Aironet Client Utility: Link Test


Aironet Client Utility: Site Survey


Link Status Meter


Installing the Client Adapter

Insert the adapter card into the PCMCIA slot in the PC


Task 4: ACU Install and Setup

From the UTILS folder on the driver CD, run SETUP

SETUP


Task 4: ACU Install and Setup (cont.)









Aironet Client Utility (ACU)



Step 12

Step 13

Step 14



Step 16

Step 17


Summary

• Identify characteristics of Cisco Aironet 802.11a products.

• Identify characteristics of Cisco Aironet 802.11b products.

777777© 2003, Cisco Systems, Inc. All rights reserved.

Documents

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—2-1 111 © 2003, Cisco Systems, Inc. All rights reserved