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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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