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CWNA Guide to Wireless LANs, Second Edition

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Title: CWNA Guide to Wireless LANs, Second Edition


1
CWNA Guide to Wireless LANs, Second Edition
  • Chapter One
  • Its 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

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

4
A Day in the Life of a Wireless User Car
  • Bluetooth wireless standard Enables short range
    wireless communication
  • Used in many small devices

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

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 e-mail servers

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

8
A Look at Wireless Technologies
  • Wireless technology woven throughout many aspects
    of life
  • Useful to get overview of some current
    technologies in todays wireless world

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

10
Wireless Local Area Networks (continued)
Figure 1-3 Wireless LAN
11
Wireless Local Area Networks (continued)
Figure 1-4 Home wireless LAN
12
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

13
Bluetooth (continued)
  • Piconet Bluetooth network containing a master
    and at least one slave

Figure 1-5 Bluetooth device
14
Telecommunications Links
  • Integrated Services Digital Networks (ISDN)
    Transmits at 256 Kbps
  • T-1 lines Transmit at 1.544 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

15
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
16
Telecommunications Links (continued)
Figure 1-7 Wireless office technologies
17
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

18
Cellular Telephony (continued)
Figure 1-8 Browsing the World Wide Web
19
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
20
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
21
Your Challange
  • Imagine this dilemma You are standing in the
    desert, overlooking 10,000 tractor-trailer-sized
    containers packed with everything needed to carry
    out a military operation. Your mission find a
    pair of size 10 boots locked away in one of those
    metal vessels.
  • What can you do?

22
RFID Technology CanSolve Your Problem
  • A small device called a radio frequency
    identification tag, or RFID tag. The tags attach
    to the containers with magnets, and each has a
    memory module that holds the bill of lading for
    its host container.
  • Wireless readers around the perimeter of these
    containers query the tags. Back-end systems
    aggregate the data and feed it into the supply
    chain, data warehousing and enterprise resource
    planning systems that help commanders get the big
    picture ... or find the boots quickly.

23
Wireless Technology Categories
Table 1-1 Typical wireless technologies
24
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

25
Wireless LAN Applications Education (continued)
Figure 1-11 Campus access point locations
26
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

27
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

28
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

29
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

30
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

31
Wireless LAN Applications Healthcare
  • Wireless LAN point-of-care computer systems allow
    medical staff to access and update patient
    records immediately
  • Document patients 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

32
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

33
Wireless LAN Applications Healthcare (continued)
Figure 1-12 Video pill
34
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 todays 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

35
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

36
Wireless Advantages and Disadvantages Advantages
(continued)
  • Disaster Recovery Documented disaster recovery
    plan vital to every business
  • Hot site Off-site facility that can run
    businesss 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

37
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

38
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

39
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

40
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)

41
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
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