Download
cwna guide to wireless lans second edition n.
Skip this Video
Loading SlideShow in 5 Seconds..
CWNA Guide to Wireless LANs, Second Edition PowerPoint Presentation
Download Presentation
CWNA Guide to Wireless LANs, Second Edition

CWNA Guide to Wireless LANs, Second Edition

185 Vues Download Presentation
Télécharger la présentation

CWNA Guide to Wireless LANs, Second Edition

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  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 e-mail 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. 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

  13. 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

  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 CWNA Guide to Wireless LANs, Second Edition

  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 CWNA Guide to Wireless LANs, Second Edition

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

  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 CWNA Guide to Wireless LANs, Second Edition

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

  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 CWNA Guide to Wireless LANs, Second Edition

  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 CWNA Guide to Wireless LANs, Second Edition

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

  22. 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

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

  24. 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

  25. 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

  26. 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

  27. 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

  28. 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

  29. 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

  30. 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

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

  32. 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

  33. 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

  34. 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

  35. 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

  36. 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

  37. 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

  38. 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

  39. 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