CWNA Guide to Wireless LANs, Second Edition

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CWNA Guide to Wireless LANs, Second Edition

• Chapter One
• Its a Wireless World

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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

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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

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A Day in the Life of a Wireless User Car

• Bluetooth wireless standard Enables short range
  wireless communication
• Used in many small devices

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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

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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

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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

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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

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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

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

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Bluetooth (continued)

• Piconet Bluetooth network containing a master
  and at least one slave

Figure 1-5 Bluetooth device
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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

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

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Cellular Telephony (continued)
Figure 1-8 Browsing the World Wide Web
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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
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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
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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?

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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.

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Wireless Technology Categories
Table 1-1 Typical wireless technologies
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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

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

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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

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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

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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

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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

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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

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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

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

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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

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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

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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

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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

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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

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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)

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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