1. CWNA Guide to Wireless LANs, Second Edition
Chapter One
It’s a Wireless World

2. Objectives
Describe how wireless technology is used in daily activities
Tell how wireless local area networks are used in applications such as education, business, travel, construction, and other areas
Explain the advantages and disadvantages of wireless technology
CWNA Guide to Wireless LANs, Second Edition

3. A Day in the Life of a Wireless User: Home
Hotspots: Locations where wireless data services are available
Wireless local area network (WLAN): Essentially identical to standard local area network (LAN)
Except devices not connected by wires
Can increase productivity
CWNA Guide to Wireless LANs, Second Edition

4. A Day in the Life of a Wireless User: Car
Bluetooth wireless standard: Enables short range wireless communication
Used in many small devices
CWNA Guide to Wireless LANs, Second Edition

5. A Day in the Life of a Wireless User: Office
Fixed broadband wireless: Wireless transmissions between immobile devices
Typically between office buildings
Utilizes small, customized antennas
Free space optics (FSO): Alternative to high-speed fiber optic transmissions
CWNA Guide to Wireless LANs, Second Edition

6. A Day in the Life of a Wireless User: Field
Handheld devices used to connect to nearest cell tower
Cell tower connects to local telephone company
Telephone company connects to appropriate resources
Such as servers
CWNA Guide to Wireless LANs, Second Edition

7. A Day in the Life of a Wireless User: On Site
Radio frequency identification (RFID) tags:
“Electronic barcodes”
Used to identify items
Can be read if anywhere within range of transmitted radio signal
Depending on device
CWNA Guide to Wireless LANs, Second Edition

8. A Look at Wireless Technologies
Wireless technology woven throughout many aspects of life
Useful to get overview of some current technologies in today’s wireless world
CWNA Guide to Wireless LANs, Second Edition

9. Wireless Local Area Networks (WLANs)
Wi-Fi (Wireless Fidelity): Based on standard that transmits at up to 11 Mbps
Computers on WLAN must have wireless network interface cards (wireless NIC or Wireless adapter)
Performs same basic functions as standard NIC, plus more
Access point (AP): Transfers signals between wireless NICs
Patch cable connects AP to wired LAN or Internet
CWNA Guide to Wireless LANs, Second Edition

10. Wireless Local Area Networks (continued)
Figure 1-3: Wireless LAN
CWNA Guide to Wireless LANs, Second Edition

11. Wireless Local Area Networks (continued)
Figure 1-4: Home wireless LAN
CWNA Guide to Wireless LANs, Second Edition

12. What is a wireless LAN?
Wireless LAN (WLAN) - provides all the features and benefits of traditional LAN technologies such as Ethernet and Token Ring, but without the limitations of wires or cables.
CWNA Guide to Wireless LANs, Second Edition

13.
What is a wireless LAN?
WLAN, like a LAN, requires a physical medium to transmit signals.
Instead of using UTP, WLANs use:
Infrared light (IR)
does include an IR specification
limitations, easily blocked, no real products (IrDA)
Radio frequencies (RFs)
Can penetrate ‘most’ office obstructions
CWNA Guide to Wireless LANs, Second Edition

14. What is a wireless LAN? More later!
WLANs use the 2.4 GHz and 5-GHz frequency bands.
ISM (Industry, Scientific, Medical) license-free (unlicensed) frequency bands.
S-Band ISM
802.11b and g: GHz
C-Band ISM
802.11a: – GHz
CWNA Guide to Wireless LANs, Second Edition

15. Icons – Wireless Devices and Functions
CWNA Guide to Wireless LANs, Second Edition

16. Icons - Buildings
CWNA Guide to Wireless LANs, Second Edition

17. Icons – Typical Wired Network Devices
CWNA Guide to Wireless LANs, Second Edition

18. Icons – Wireless LAN Antenna
CWNA Guide to Wireless LANs, Second Edition

19. IEEE 802.11 and the Wi-Fi Alliance
IEEE LAN/MAN Standards Committee (LMSC)
First standard released in 1997, several since then
Wireless Ethernet Compatibility Alliance (WECA)
Advertises its Wi-Fi (wireless fidelity) program
Any vendor can have its products tested for interoperability
Cisco is a founding member
CWNA Guide to Wireless LANs, Second Edition

20. Wi-Fi™ Wi-Fi™ Alliance Wi-Fi’s™ Mission WECA changed its name to Wi-Fi
Wireless Fidelity Alliance
170+ members
Over 350 products certified
Wi-Fi’s™ Mission
Certify interoperability of WLAN products (802.11)
Wi-Fi™ is the “stamp of approval”
Promote Wi-Fi™ as the global standard
CWNA Guide to Wireless LANs, Second Edition

21. Other Wireless Technologies
Not discussed in this course:
Cellular
Bluetooth or PAN (Personal Area Network)
3G (3rd Generation)
UWB (Ultra Wide Band)
FSO (Free Space Optics)
Radio waves off meteor trails!
CWNA Guide to Wireless LANs, Second Edition

22. Why Wireless?
CWNA Guide to Wireless LANs, Second Edition

23. WLAN Evolution Warehousing Retail Healthcare Education Businesses Home
Radio
Network
Speed
860 Kbps
900 MHz
1 and 2 Mbps
2.4 GHz
Proprietary
1 and 2 Mbps
11 Mbps
54 Mbps
Standards-based
2.4 GHz
5 GHz
IEEE Begins Drafting
Ratified
802.11a,b Ratified
802.11g Drafted
1986
1988
1990
1992
1994
1996
1998
2000
2002

24. Current Standards – a, b, g
Radio
Network
Speed
860 Kbps
900 MHz
1 and 2 Mbps
2.4 GHz
Proprietary
1 and 2 Mbps
11 Mbps
54 Mbps
Standards-based
2.4 GHz
5 GHz
IEEE Begins Drafting
Ratified
802.11a,b Ratified
802.11g Ratified
1986
1988
1990
1992
1994
1996
1998
2000
2003
802.11a
Up to 54 Mbps
5 GHz
Not compatible with either b or g
802.11b
Up to 11 Mbps
2.4 GHz
802.11g
802.11g is backwards compatible with b, but with a drawback (later)
CWNA Guide to Wireless LANs, Second Edition

25. 802.11 PHY (Physical Layer) Technologies
Radio
Network
Speed
860 Kbps
900 MHz
1 and 2 Mbps
2.4 GHz
Proprietary
1 and 2 Mbps
11 Mbps
54 Mbps
Standards-based
2.4 GHz
5 GHz
IEEE Begins Drafting
Ratified
802.11a,b Ratified
802.11g Ratified
1986
1988
1990
1992
1994
1996
1998
2000
2003
Infrared light
Three types of radio transmission within the unlicensed 2.4-GHz frequency bands:
Frequency hopping spread spectrum (FHSS) b (not used)
Direct sequence spread spectrum (DSSS) b
Orthogonal frequency-division multiplexing (OFDM) g
One type of radio transmission within the unlicensed 5-GHz frequency bands:
Orthogonal frequency-division multiplexing (OFDM) a
CWNA Guide to Wireless LANs, Second Edition

26. Major Factors
There are four major factors to consider before implementing a wireless network:
High availability
Scalability
Manageability
Open architecture
CWNA Guide to Wireless LANs, Second Edition

27. Atmosphere: the wireless medium
Wireless signals are electromagnetic waves
No physical medium is necessary
The ability of radio waves to pass through walls and cover great distances makes wireless a versatile way to build a network.
CWNA Guide to Wireless LANs, Second Edition

28. Electromagnetic Spectrum
The Electromagnetic Spectrum Chart
The waves differ only in their frequency.
All of these waves share some very important characteristics.
Travel at the speed of light
Obey the equation (frequency) x (wavelength) = c (speed of light).
Very different interactions with various materials.
Low frequency electromagnetic waves have a long wavelength, while high frequency electromagnetic waves have a short wavelength.
Wavelength represents the distance from one peak to the next on the sine wave.
CWNA Guide to Wireless LANs, Second Edition

29. The Electromagnetic Wave Equation
CWNA Guide to Wireless LANs, Second Edition

30. The size of a bit “Speed of the link” or “Speed of the network”
Sometimes we forget that the speed of the data always travels near the speed of light:
180,000 miles/second or 300,000 meters/second
What changes is the length of the bit.
Using the formula: speed of light = frequency x wavelength
1 bps =
CWNA Guide to Wireless LANs, Second Edition

31. Distance versus Speed
WLANs are only one usage of the radio frequency (RF) spectrum.
CWNA Guide to Wireless LANs, Second Edition

32. Bluetooth Low-power wireless data and voice transmission technology
Bluetooth devices communicate via radio modules
Link manager: Software that helps identify other Bluetooth devices, creates links between devices, and sends and receives data
Transmit data at up to 1 Mbps over 10 meters
Bluetooth devices within range of each other automatically connect
Master and slave
CWNA Guide to Wireless LANs, Second Edition

33. Bluetooth (continued)
Piconet: Bluetooth network containing a master and at least one slave
Figure 1-5: Bluetooth device
CWNA Guide to Wireless LANs, Second Edition

34. Bluetooth
Uses devices with small radio transceivers, called radio modules, built onto microprocessor chips
Special software, called a link manager, identifies other Bluetooth devices, creates links with them, and sends and receives data
Transmits at up to 1 Mbps over a distance of 33 feet and is not impeded by physical barriers
Bluetooth products created by over 1500 computer, telephone, and peripheral vendors
CWNA Guide to Wireless LANs, Second Edition

35. Bluetooth Headset
The Bluetooth headset automatically establishes a connection with the telephone
CWNA Guide to Wireless LANs, Second Edition

36. Piconet
Two or more Bluetooth devices that send and receive data make up a personal area network (PAN), also called a piconet
Figure 1-3 shows a Bluetooth network
Bluetooth was named after the 10th century Danish King Harold Bluetooth, who was responsible for unifying Scandinavia
CWNA Guide to Wireless LANs, Second Edition

37. Bluetooth Network
CWNA Guide to Wireless LANs, Second Edition

38. Telecommunications Links
Integrated Services Digital Networks (ISDN): Transmits at 256 Kbps
T-1 lines: Transmit at Mbps
Cable modems: Use television cable connection
Digital subscriber lines (DSL): Use telephone lines
WiMax: Signal transmitted between antennas
Up to 75 Mbps and over up to 35 miles
Fixed Broadband
CWNA Guide to Wireless LANs, Second Edition

39. Telecommunications Links (continued)
FSO: Transmit at speeds up to 1.25 Gbps over up to 4 miles
Line-of-site transmission
Figure 1-6: Free space optics transceiver
CWNA Guide to Wireless LANs, Second Edition

40. Telecommunications Links (continued)
Figure 1-7: Wireless office technologies
CWNA Guide to Wireless LANs, Second Edition

41. 2G Digital Cellular Personal Digital Assistant (PDA) Hand-held device
May include a barcode scanner and keyboard, as shown in Figure 1-6
Data may be transmitted to a terminal using wireless digital cellular technology
CWNA Guide to Wireless LANs, Second Edition

42. Three Standards
The second generation (2G) standard sends data at rates up to 14 thousand bits per second (kilobits per second or Kbps)
In the future, the third generation (3G) technology may transmit up to 2 Mbps using a universal standard
An interim technology known as 2.5 G offers a bandwidth of up to 384 Kbps
CWNA Guide to Wireless LANs, Second Edition

43. Digital Cellular Network
CWNA Guide to Wireless LANs, Second Edition

44. Cellular Telephony
Global Systems for Mobile (GSM) communications technology: Coverage includes most of US and parts of Europe and Japan
Transmission speeds up to 9.6 Kbps
Information transmitted based on Wireless Application Protocol (WAP)
Standard way to transmit, format, and display data for devices like cell phones and handheld devices
CWNA Guide to Wireless LANs, Second Edition

45. Cellular Telephony (continued)
Figure 1-8: Browsing the World Wide Web
CWNA Guide to Wireless LANs, Second Edition

46. Cellular Telephony (continued)
WAP cell phone runs a microbrowser that uses Wireless Markup Language (WML) instead of HTML
WAP gateway or proxy: Translates between WML and HTML
Figure 1-9: WAP communications
CWNA Guide to Wireless LANs, Second Edition

47. Radio Frequency Identification (RFID)
Like an electronic barcode:
Can contain larger amounts of updatable information
Information transmitted via radio waves
Range typically about 1 foot at 5 Mbps
Figure 1-10: RFID tag
CWNA Guide to Wireless LANs, Second Edition

48. Fixed Broadband Wireless and Other Alternatives
Integrated Service Digital Networks (ISDN)—consist of leased lines that transmit at 256 Kbps
Expensive T-1 lines—transmit at Mbps
Cable modems—use television cable connections
Digital subscriber lines (DSL)—have limited availability
Fixed broadband wireless—a faster less expensive choice
CWNA Guide to Wireless LANs, Second Edition

49. Fixed Broadband Wireless
Fixed broadband transmits as far as 35 miles at speeds up to 1 billion bits per second (gigabits or Gbps) for downloads and 512 Kbps for uploads
Uses small custom antenna on roof of each connected building
Figure 1-11 shows fixed broadband wireless network
CWNA Guide to Wireless LANs, Second Edition

50. Fixed Broadband Wireless Network
CWNA Guide to Wireless LANs, Second Edition

51. Satellite Transmits data to/from satellite circling the earth
A repeater in the satellite simply “repeats” the signal to another location
Earth station transmits at one frequency and receives the signal at another frequency
Transmission time from one earth station to another is approximately 250 milliseconds
See Figure 1-4
CWNA Guide to Wireless LANs, Second Edition

52. Satellite Frequency Transmission
CWNA Guide to Wireless LANs, Second Edition

53. A Satellite Network
CWNA Guide to Wireless LANs, Second Edition

54. Wireless Technology Categories
Table 1-1: Typical wireless technologies
CWNA Guide to Wireless LANs, Second Edition

55. Wireless LAN Applications: Education
Educational institutions some of first adopters of WLANs
Dramatic advantages in teaching and learning
Wireless LAN connections offer students important degree of freedom
WLAN technology translates into cost savings for colleges
Reduces need for wiring and infrastructure
Fewer computer labs necessary
CWNA Guide to Wireless LANs, Second Edition

56. Wireless LAN Applications: Education (continued)
Figure 1-11: Campus access point locations
CWNA Guide to Wireless LANs, Second Edition

57. Wireless LAN Applications: Business
Wireless LAN technologies have significantly changed how business conducted
Meetings not confined to conference rooms
Easier to connect to network resources and Internet
Can create office in space where traditional infrastructure does not exist
CWNA Guide to Wireless LANs, Second Edition

58. Wireless LAN Applications: Travel
Travel industry perhaps adopted wireless technologies more than any other industry
Many airport terminals provide wireless hotspots
Several large airlines providing wireless capabilities to passengers during flights
Some airlines use WLAN technology to communicate with aircraft on ground
Some airlines use WLAN technology to facilitate maintenance tasks
Some airlines use new wireless data service to send and receive messages
CWNA Guide to Wireless LANs, Second Edition

59. Wireless LAN Applications: Construction
Wireless technology has greatly benefited construction industry
Better management of resources
Better management of paperwork
Construction equipment being fitted with wireless terminals
“Smart” equipment
GPS information can provide location information to within centimeters
CWNA Guide to Wireless LANs, Second Edition

60. Wireless LAN Applications: Warehouse Management
New products arrive continuously
Must be inventoried and stored
Products being shipped must first be located then transferred to correct location and truck
Mistakes in inventory or inability to locate items can be devastating
Mark inventory with RFID tags
Warehouse management system (WMS) software: Can manage all activities from receiving through shipping
Utilize wireless technology
CWNA Guide to Wireless LANs, Second Edition

61. Wireless LAN Applications: Public Safety
Public safety departments using WLANs and GSM to communicate information with public safety vehicles
City-owned buildings equipped with APs
Large volumes of data can be quickly downloaded to vehicles
e.g., building floor plans, photographs of criminal suspects, and maps
CWNA Guide to Wireless LANs, Second Edition

62. Wireless LAN Applications: Healthcare
Wireless LAN point-of-care computer systems allow medical staff to access and update patient records immediately
Document patient’s medication administration immediately
Extensive use of RFID tags
Identify healthcare professionals, patients, medications
System verifies that medication being administered to correct patient in correct dosage
Eliminates potential errors and documentation inefficiencies
CWNA Guide to Wireless LANs, Second Edition

63. Wireless LAN Applications: Healthcare (continued)
Documentation process takes place at bedside where care delivered
Improves accuracy
Hospital personnel have real-time access to latest medication and patient status information
Wireless technology also used in other medical areas:
e.g., video pills
CWNA Guide to Wireless LANs, Second Edition

64. Wireless LAN Applications: Healthcare (continued)
Figure 1-12: Video pill
CWNA Guide to Wireless LANs, Second Edition

65. Wireless Advantages and Disadvantages: Advantages
Mobility: Primary advantage of wireless technology
Enables individuals to use devices no matter where users roam within range of network
Increasingly mobile workforce is characteristic of today’s business world
WLANs give mobile workers freedom while allowing them to access network resources
“Flatter” organizations: WLANs give team-based workers ability to access network resources needed while collaborating in team environment
CWNA Guide to Wireless LANs, Second Edition

66. Wireless Advantages and Disadvantages: Advantages (continued)
Easier and Less Expensive Installation: Installing network cabling in older buildings difficult and costly
Wireless LAN is ideal solution
Eliminating need for cabling results in cost savings
Significant time savings as well
Allows offices to reorganize easily
Increased Reliability: Wireless LAN technology eliminates certain types of cable failures and increases overall network reliability
CWNA Guide to Wireless LANs, Second Edition

67. Wireless Advantages and Disadvantages: Advantages (continued)
Disaster Recovery: Documented disaster recovery plan vital to every business
Hot site: Off-site facility that can run business’s operations if primary site is not available
Generally maintained by third party
Expensive
Cold site: Customer provides and installs equipment
Many businesses use cold sites and WLANs as major piece of disaster recovery plan
No consideration given to network cabling
CWNA Guide to Wireless LANs, Second Edition

68. Wireless Advantages and Disadvantages: Disadvantages
Security: Wireless signals broadcast in open air
Security for wireless LANs is prime concern
Unauthorized users might access network
War driving
Attackers might view transmitted data
Employees could install rogue access points
Attackers could easily crack existing wireless security
Older wireless products have very weak security features
CWNA Guide to Wireless LANs, Second Edition

69. Wireless Advantages and Disadvantages: Disadvantages (continued)
Radio Signal Interference: Signals from other devices can disrupt wireless transmissions
Or wireless device may be source of interference for other devices
e.g., Microwave ovens, elevator motors, photocopying machines, theft protection devices, cordless telephones
Solution: Locate source of interference and remove
Health Risks: Wireless devices emit RF energy
Not known if or to what extent low levels of RF might cause adverse health effects
CWNA Guide to Wireless LANs, Second Edition

70. Summary
Wireless devices and technologies enable users to roam almost anywhere and remain connected to data and voice networks
A WLAN, also known as Wi-Fi, functions the same as a standard wired network except devices send radio frequency signals through the air instead of being connected to the network by cabling
Bluetooth devices communicate using small radio transceivers called radio modules that are built into microprocessor chips
CWNA Guide to Wireless LANs, Second Edition

71. Summary (continued)
Two popular technologies are WiMax and free space optics (FSO)
Handheld devices can send and receive wireless signals using the Global System for Mobile (GSM) communications technology
RFID tags function as electronic barcodes
Wireless personal area networks (WPANs) cover technologies where the transmission generally extends only a few meters or feet, whereas wireless local area networks (WLANs) are generally restricted to 112 meters (375 feet)
CWNA Guide to Wireless LANs, Second Edition

72. Summary (continued)
Wireless LAN applications can be found in industries in which employees need the freedom to conduct business without being confined to a specific location
Wireless LANs have significant advantages, including increased mobility, easier and less expensive network installations, increased network reliability, and disaster recovery
Some of the disadvantages of wireless LANs include security, radio signal interference, and health concerns
CWNA Guide to Wireless LANs, Second Edition