1. IFIP-UNU ADVANCED COURSE ON NETWORKING AND SECURITY Module II-Wireless Communications Section 2
The IEEE Protocol

2. Learning Objectives Identify the IEEE 802. standards.
Understand the MAC and PHY layers of
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.

3. Overview
This chapter will cover the IEEE 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.

4. Key terms
IEEE
MAC
PHY
NIC
STA
MSDU
PLCP
PMD
BSS

5. Standards

6. 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 ( GHz)
802.11k: Measurement
802.11m: Maintenance
802.11n: High-Speed

7. 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 a products:
U.S. Australia Austria Denmark France Sweden New Zealand Ireland Japan Singapore Taiwan Argentina
U.K. Germany Norway Portugal Canada Belgium Netherlands Finland Poland Switzerland Mexico
802.11h will ultimately permit worldwide usage of 5 GHz
Transmit Power Control (TPC)
Dynamic Frequency Selection (DFS)
GHz band being opened up (11 more channels)
This new GHz band, plus 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

8. Three Wireless Technologies
802.11b
802.11a
802.11g
Frequency
Band
2.4 GHz
5 GHz
2.4 GHz
Availability
Worldwide
US/AP
Worldwide
Maximum Data rate
11 Mbps
54 Mbps
54 Mbps
Cordless Phones Microwave Ovens Wireless Video Bluetooth Devices
Cordless Phones Microwave Ovens Wireless Video Bluetooth Devices
Other
Services
(Interference)
HyperLAN Devices
The Laws of Radio Dynamics:
Higher Data Rates = Shorter Transmission Range Higher Power Output = Increased Range, but Lower Battery Life Higher Frequency Radios = Higher Data Rates Shorter Ranges

9. 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 a and b became standards in September 1999
802.11a – 5 GHz at 54 Mbps OFDM
802.11b – 2.4 GHz at 11 Mbps DSSS
IEEE g is scheduled to be ratified in 2003
802.11g – 2.4 GHz at 54 Mbps OFDM
promises “true” vendor interoperability

10. Standards and Organizations

11. WLAN Speeds & Frequencies
802.11g
2.4 GHz – OFDM/CCK
54 Mbps
802.11a
5 GHz – OFDM
54 Mbps
802.11b
2.4 GHz – CCK
11 Mbps
Proprietary
IEEE a/b Ratified
Jan’99
Jan’00
Jan’01
Jan’02
Jan’03
Jan’04

12. What Is WLAN RF Technology?
This section discusses theories and processes of using Spred Spectrum technology to send data over an RF signal.
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)
Spread Spectrum is a type of emission designed to be somewhat immune to interference, difficult to detect, and hard to intercept.
Actress Hedy Lamarr and music composer George Antheil patented the concept of Spread Spectrum in The idea was a method for guiding a torpedo without interference from a jamming signal.
In 1986, the FCC agreed to allow the use of Spread Spectrum in the commercial market under the ISM bands.
Just as the radio in your car has AM (Amplitude Modulation) and FM (Frequency Modulation) bands, other radios use different bands and types of modulation.

13. IEEE 802. Standards

14. Architecture

15. 802.11 Physical (PHY) Layer Modulations

16. Stations (STA)

17. PHY Protocols

18. Basic Service Set (BSS)

19. Independent Basic Service Set (IBSS)

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

21. MAC Layer

22. MAC Services

23. MAC Architecture

24. CSMA

25. Interframe Spaces

26. PHY Layer

27. PHY Functions

28. 802.11b

29. Europe, Middle East and Asia
2.4 GHz Channel Sets
Regulatory Domain
Channel Identifier
Center Frequency
Americas
Europe, Middle East and Asia
Japan
Israel X X 1 2 3 4 5 6 7 8 9 10 11 12 13 14
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 X X

30. Channels- 2.4 GHz DSSS 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
11 “chips per bit” means each bit sent redundantly
11 Mbps data rate
3 access points can occupy same area

31. 802.11b Access Point Coverage
1 Mbps DSSS
2 Mbps DSSS
5.5 Mbps DSSS
11 Mbps DSSS

32. 802.11b Scalability Total Theoretical Bandwidth = 33 Mbps
Blue = 11 Mbps
Green = 11 Mbps
Red = 11 Mbps

33. Comparing the Technologies 802.11a Data Rates
Data Rate Per Subchannel (Kbps)
Modulation with Sub Channels
Total Data Rate (Mbps)
BPSK
125 6
BPSK
187.5 9
QPSK
250 12
QPSK
375 18
16QAM
500 24
16QAM
750 36
64QAM
1000 48
64QAM
1125 54

34. 802.11a Channel Sets Americas include: Argentina Australia Austria
Americas (-A)
Japan (-J)
Singapore (-S)
Taiwan (-T) 34
5170 x 36
5180 38
5190 40
5200 42
5210 44
5220 46
5230 48
5240 52
5260 56
5280 60
5300 64
5320 20
Channel Set
Cisco Maximum Peak Power (mW)*
Channel ID
Frequency
(MHz)
Americas include:
Argentina
Australia
Austria
Brazil
Canada
Chile
Columbia
Denmark
France
Mexico
New Zealand
Panama
Peru
Sweden
United Kingdom
United States
Venezuela
Assuming a 6 dBi antenna (The radiated power is):
UNII-1 – 50 mW in the US/Japan, 200mW in Europe, 4 Channels ( ), Indoor Access- Fixed Antenna
UNII-2 – 250 mW in US, 4 Channels ( )- Indoor/Outdoor Use – Flexible Antenna
UNII-3 – 1 W in the US, 4 Channels ( ) – Outdoor Bridging only
HiperLAN – 200 mW in Europe, 8 Channels ( ) – Indoor Use only
HiperLAN– 1W in Europe, 11 channels ( ) – Indoor/Outdoor Use –Flexible Antenna

35. 802.11a Access Point Coverage
OFDM
54 Mbps
48 Mbps
36 Mbps
24 Mbps
18 Mbps
12 Mbps
09 Mbps
06 Mbps

36. 802.11a Scalability (Indoor UNII-1 and 2)
Total Theoretical Bandwidth = 432 Mbps
8 non-overlapping channels
54 Mbps
54 Mbps
54 Mbps
54 Mbps
54 Mbps
54 Mbps
54 Mbps
54 Mbps

37. Client Adapters

38. Cisco Aironet 802.11b Client Adapters
2.4 GHz
802.11b
11 Mbps
Include
PC Card
PCI Card
LMC Card
Mini PCI

39. 802.11b PC Card 2.4 GHz/802.11b Rate Shifting Fixed data rates
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

40. 802.11b LMC Card 2.4 GHz/802.11b Rate Shifting Fixed data rates
11 Mbps
Rate Shifting
1, 2, 5.5, and 11Mbps
Fixed data rates
User configurable option
PCMCIA interface
Transmit power settings:
100 mW, 50 mW, 30 mW, 20 mW, 10 mW, 5 mW, and 1 mW

41. 802.11b PCI Card 2.4 GHz/802.11b Rate Shifting Fixed data rates
11 Mbps
Rate Shifting
1, 2, 5.5, and 11Mbps
Fixed data rates
User configurable option
RP-TNC Connector
PCMCIA interface
Transmit power settings:
100 mW, 50 mW, 30 mW, 20 mW, 10 mW, 5 mW, and 1 mW

42. 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)

43. 802.11a CardBus2 Client Adapter
5 GHz/802.11a
54 Mbps
Rate Shifting
6, 9, 12, 18, 24, 36, 48, or 54
Fixed data rates
User configurable option
5 dBi Patch Antenna
CardBus interface
Transmit power settings:
20 mW, 10 mW, and 5 mW

44. PC Card LEDs Dual LED helps identify the card status
Green LED is the Status LED
Orange LED is the RF traffic LED

45. LED Status

46. Windows Drivers

47. Linux and Macintosh Drivers

48. Downloading Drivers and Software

49. Ad-Hoc

50. Infrastructure

51. Aironet Client Utility (ACU)

52. Aironet Client Utility: Main Screen

53. Aironet Client Utility: Loading Firmware

54. Aironet Client Utility: Profile Manager

55. Aironet Client Utility: Adding a Profile

56. Profile: System Parameters

57. Profile: RF Network

58. Profile: RF Network

59. Profile: Advanced (Infrastructure)

60. Profile: Advanced (Ad Hoc)

61. Profile: Network Security

62. Aironet Client Utility: Status

63. Aironet Client Utility: Statistics

64. Aironet Client Utility: Link Test

65. Aironet Client Utility: Site Survey
The Site Survey utility allows a user to perform a site survey to determine the best placement of the access points in order to provide the desired coverage.
The Site Survey can run in either Passive or Active mode. The Active mode is used to perform site surveys.
The Site Survey utility can be set to display results as percentages, or as actual values (for example, as dBm, or decibels per milliwatt). Complete the following steps to switch from percentage to dBm.
1. Click on the Preferences icon on the main page.
2. Select the dBm radio button under Signal Strength Display Units .
Now your ACU Site Survey will show signal to noise ratio.

66. Link Status Meter

67. Labs

68. Labs of Section 2 Lab 2.4.3 Install a WLAN Adapter Card
Lab Install Aironet Client Utility (ACU)
Lab Configure Auto Profiles
Lab ACU Utilities
Lab Creating an Adhoc Network