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Wireless networking

Wireless networking. Unit objectives Identify the hardware components needed to create a wireless connection Differentiate between the various communications standards used in wireless networks Install and configure a wireless network connection. Topic A. Topic A: Wireless network devices

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Wireless networking

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  1. Wireless networking Unit objectives • Identify the hardware components needed to create a wireless connection • Differentiate between the various communications standards used in wireless networks • Install and configure a wireless network connection

  2. Topic A • Topic A: Wireless network devices • Topic B: Wireless networking standards • Topic C: Wireless configuration

  3. Wireless • Technologies and systems that don’t use cables for communication • Examples • Public radio • Cellular telephones • One-way pagingSatellite • Infrared • Private, proprietary radio • Wireless networks – LAN or WAN

  4. Wireless connections • Can link devices • Methods • Infrared • Radio • Bluetooth • Infrared and Bluetooth • Create wireless connection between two devices • Radio technology • Forms larger wireless network

  5. Infrared • Uses pulses of invisible infrared light to transmit signals • Low-speed, line-of-sight connection • Can’t pass through obstructions or around corners • 9600 bps to 4 Mbps data rate • 10-20 feet maximum range • Devices must aim their transceivers at each other (line-of-sight technology) continued

  6. Infrared, continued • No more than a 45 degree angle • Most popular form: Infrared Serial Data Link technology • Serial connection • 1.5 Mbps • 20 foot range • Often found on laptops and PDAs

  7. Radio • Signals sent over electromagnetic radio waves • Can pass through most nonmetallic obstructions and around corners • Not a line-of-sight technology • Offers moderate- to high-speed local and wide area connections • Most common technologies: • 802.11b • 802.11g continued

  8. Radio, continued • 10 Mbps • Sometimes called RF technologies • RF stands for radio frequency • RF devices have antennae

  9. Bluetooth • Short-distance radio (up to 10 meters) • Developed by the Bluetooth Special Interest Group • Includes over 1,000 companies • Siemens, Intel, Toshiba, Motorola, and Ericsson • Enables devices to discover other Bluetooth devices within range • Devices self-configure and begin communicating continued

  10. Bluetooth, continued • Shouldn’t need to configure communication parameters • Bluetooth devices have antenna often hidden inside the device

  11. Wireless communications • Enables users to • Make Internet connection while traveling • Connect to network while moving about house or office • Important technology for • Mobile devices • Internet access in remote locations • Three types of wireless links • Indoor point-to-multipoint LANs • Outdoor point-to-point links • Outdoor point-to-multipoint links

  12. Indoor point-to-mulitpoint LANs

  13. Outdoor point-to-point links

  14. Outdoor point-to-multipoint links

  15. Wireless connection components • Requires • Wireless network card in the computer • Wireless router or wireless access point device on the network • Router or WAP broadcasts radio signals • Wireless network cards pick up the broadcasts

  16. Wireless NICs

  17. Wireless access points

  18. Wireless speeds • Distance and data rate affected by • Obstructions within building • Environment noise • Recommend wireless LAN access points within 60 to 90 meters of wireless clients

  19. WAP placement • Informal site survey • Temporary installation WAPs • Use wireless client to test signal • Use actual locations for clients • Formal site survey • Use field-strength measuring equipment • Install test antenna in the estimated WAP locations • Strength of test signal at various points within the range the WAP will service • Move test antenna to obtain the best possible signal for the wireless coverage area

  20. Activity A-1 Examining wireless devices

  21. Topic B • Topic A: Wireless network devices • Topic B: Wireless networking standards • Topic C: Wireless configuration

  22. Standards • Frequency bands divisions • Military • Broadcasters • Amateur radio operators • Broadcast signal is a security issue • IEEE standards 802.1x and 802.11

  23. 802.1x standard • Port-based, authentication framework for access to Ethernet networks • Designed for wired Ethernet networks • Applies to 802.11 WLANs • Requires three roles in authentication process • Device requesting access • Authenticator • Authentication server • Allows multiple authentication algorithms • Is an open standard

  24. 802.11 standard • Operates in the 2.4 through 2.5GHz band • Used for wireless networks • OSI Data Link layer • Two ways to configure a network • Ad-hoc • Infrastructure • Places specification on Physical and MAC layers

  25. Access point • Transparent bridge between wireless clients and wired network • Includes • At least one interface to connect to the existing wired network • Transmitting equipment to connect with wireless clients • IEEE 802.1D bridging software

  26. 802.11a 802.11b 802.11c 802.11d 802.11e 802.11F 802.11g 802.11h 802.11i 802.11j 802.11k 802.11l 802.11m 802.11n 802.11 WLAN standards

  27. Wireless protocols • Wi-Fi (Wireless Fidelity) • IEEE 802.11b: 11 Mbps; 2.4 GHz band • IEEE 802.11g: 20+ Mbps; 2.4 GHz band; transmission range of up to 35 meters • Experience interference from other common household devices • Bluetooth • Short-range: about 100 meters or less • Low speeds: 721 Kbps continued

  28. Wireless protocols, continued • 802.11a • Improved version of original Wi-Fi • 54 Mbps; 5 GHz band • Indoor range of up to 35 meters • Not compatible with 802.11b devices • WiMAX (IEEE 802.16 Air Interface Standard) • Point-to-multipoint broadband access • 10-66 GHz licensed • 2-11 GHz unlicensed • 70 Mbps • 31 miles; direct line-of-site

  29. LAN technologies • IEEE 1394 • FireWire (Sony) and iLink (Apple) • Main use: video and graphics transfers • Serial protocol • FireWire 400: 100 to 400 Mbps • FireWire 800: up to 800 Mbps • USB • Bidirectional serial interface • Main use: connect peripheral devices • USB 1.1: 1 to 12 Mbps • USB 2.0: 480 Mbps

  30. Wi-Fi • Called AirPort. 802.11b • Frequency range of 2.4 GHz • Distance range of about 100 meters • Up to 11 Mbps • Range depends on type of signal obstructions between transmitter and receiver • 802.11b – popular and inexpensive network solution • Many cordless phones use the 2.4-GHz frequency and can interfere with 802.11b network

  31. Bluetooth • Standard for short-range wireless communication and data synchronization between devices • Transmitters and receivers are application-specific integrated circuits (ASICs) • Can transmit data at rates as high as 721 Kbps • Up to three voice channels available • Easy to configure

  32. 802.11a/802.11g • 802.11a • 5.0-GHz band • Isn’t compatible with 802.11b • 50 meters max between AP and client • Faster than 802.11b • Doesn’t encounter interference from 2.4 MHz devices • 802.11g • 2.4-GHz band • Backwards compatible with 802.11b • 54 Mbps

  33. WiMAX • Worldwide Interoperability of Microwave Access • Wireless DSL and T1-level service • Emerging Wide Area and Metropolitan Area Networks technology standard • Enables 802.16e devices to roam between current wireless hot spots • Coverage measured in square miles • Doesn’t rely on line-of-sight for connection

  34. Activity B-1 Comparing wireless networking standards

  35. Topic C • Topic A: Wireless network devices • Topic B: Wireless networking standards • Topic C: Wireless configuration

  36. WLAN security risks • Devices can be lost or stolen • Session hijacking • Man-in-the-middle attacks • Rogue AP • WAP no default security • Broadcasts make breaking in easy • IEEE and WECA developed standards for user authentication and media access control

  37. Additional risks • Detectable radio-frequency traffic • Data is passed in clear text form • Encryption isn’t always strong • WEP • One-way authentication mechanism • One-way open broadcast client connection • Wardriving • Warchalking

  38. WLAN security components • Access control • Turn off SSID broadcasts • Enable a MAC filter on your AP • Encryption • Clients and AP use same encryption scheme • Clients must possess correct encryption key • Wireless encryption systems vary in ability to keep data secure continued

  39. WLAN security, continued • Authentication • Server authenticates clients • Stronger access control protection than SSID hiding or MAC filtering • Should still use encryption • Isolation • Segregates network traffic • Two types: wireless client isolation (AP isolation) and network isolation • Network isolation through custom routing • Isolation through your general network design and firewall configuration

  40. Transmission encryption • Wired Equivalent Privacy (WEP) • Wi-Fi Protected Access (WPA) Personal • WPA2 • WPA Enterprise • RADIUS • 802.11i

  41. 802.1x authentication

  42. Activity C-1 Identifying the technology used to implement WLANs

  43. Wireless access point configuration • Assign a service set identifier (SSID) • Clients use the SSID to distinguish between WLANs • AP typically broadcasts the SSID • Broadcasts identify the security mechanisms to enable clients to auto-configure connections

  44. Securing your AP • Set most secure encryption method compatible with clients • Change AP default admin passwords • Change default SSID • Disable SSID broadcasts • Separate wireless network from wired network • Put wireless network in an Internet-access only zone or DMZ continued

  45. Securing your AP, continued • Disable DHCP within WLAN • Enable MAC address filtering on AP • Enable 802.1x • Periodically survey site with wireless sniffing tool

  46. Activity C-2 Configuring a wireless access point (instructor demo)

  47. Wireless clients • Submit its credentials to the Authenticating server • Secured or 802.1x authenticated connections • Wireless AP issues a challenge to the client • AP sets up restricted channel allowing client to communicate only with RADIUS server • RADIUS server accepts only trusted AP connections • RADIUS server validates the client credentials • Transmits client master key to wireless AP

  48. Wireless Auto Configuration • Dynamically selects wireless network connection attempt • Based on • Configured preferences • Default settings • Wireless Zero Configuration • Windows Vista • Windows XP • Windows 2000 with download • Automatically configures address items: • TCP/IP settings, • DNS server addresses • IAS server addresses

  49. Auto Configuration, continued • IEEE 802.1x authentication defaults • Infrastructure before ad hoc mode • Computer authentication before user authentication. • If NIC is preconfigured with WEP shared key, attempts to perform IEEE 802.11 shared key authentication; otherwise NIC reverts to open system authentication

  50. Windows CE wireless clients • Windows CE .NET palm-top computers include Wireless Zero Configuration • Manual configuration options similar to those found on Windows Vista and Windows XP • Supports 802.11a and Native Wireless Fidelity (Wi-Fi) • Non-.NET palm-tops wireless configuration is like Windows 2000

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