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Wireless

Wireless. Networking. Ubiquitous Wireless. IrDA (Infrared Data Association) gets combined with RF – but who uses it now? IrDA uses a transceiver port on older laptops and PDAs New laptops come with wireless built-in And we cannot forget smartphones Ubiquitous means “all over the place”

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Wireless

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  1. Wireless Networking

  2. Ubiquitous Wireless • IrDA (Infrared Data Association) gets combined with RF – but who uses it now? • IrDA uses a transceiver port on older laptops and PDAs • New laptops come with wireless built-in • And we cannot forget smartphones • Ubiquitous means “all over the place” • Based on 802.11 standard

  3. Wireless Components • WAP – Wireless Access Point • Uses Carrier Sense Multiple Access/Collision Avoidance – listen for traffic, then send when clear • Need a wireless adapter and device drivers • Can be Power Over Ethernet (PoE) • Replaces Layer One and part of Layer Two in OSI model

  4. Ad Hoc mode • Two or more computers talking to each other • No central point of connection • Agree on IP address range/assignment, common subnet mask and net name and you are good to go. • You now have an Independent Basic Service Set (IBSS)

  5. Ad-hoc Mode • Everybody talks to each other, or Peer-to-Peer

  6. Infrastructure Mode • Infrastructure means that we have one, or more, access point(s) • One access point is a Basic Service Set (BSS) • Two or more access points are an Extended Basic Service Set (EBSS) • Takes planning to set up (especially EBSS)

  7. Infrastructure Mode • Use one or more WAPs to connect wireless clients to wired network Router

  8. SSID • Service Set Identifier • Also known as network name • Defines the wireless network • Common thought is to try to hide the SSID • CompTIA thinks it is a good idea • Not the best idea as management frames contain SSID – hidden or not

  9. MAC address filtering • Create a list of who is allowed access to network from the MAC addresses of clients • Again, this is supposed to be good • A determined hacker can sniff out MAC address and “spoof” it to gain access

  10. WEP • The whipping boy of wireless • Wired Equivalent Privacy • Can be cracked in 5 minutes with right software • Who has the right software … • Even the longer key is not much benefit (40 and 104 bits) • Our casual, curious George will not have the tools to crack WEP (i.e. the right software) • Encryption from WAP to device

  11. WPA • Wi-Fi Protected Access • Came out before the standard (.11i) was finalized/ratified • Uses Temporal Key Integrity Protocol (TKIP); new key for every packet sent • User authentication with Extensible Authentication Protocol (EAP)

  12. WPA 2 • Complies with .11i standard • Uses Advanced Encryption Standard (AES) • Supposed to be the Fort Knox of wireless

  13. WPS • Since most people don’t set up security… • Wi-Fi Protected Setup • Button on router, password or code • Fairly easy to crack by guessing the eight-digit code

  14. Standards

  15. Bluetooth • Named after Danish King – not Big Blue (IBM) • 802.15 standard • Max of about 3 Mbps with gen 2 equipment • Keyboards and mice • Designed to be a helper not a full network

  16. Cellular • Uses the cell network to be the wireless network • 1.5 Mbps download in big cities • Pricey way to connect your laptop, but cool ! You can “connect” from anywhere you can get cell reception

  17. Installing • What gets changed is half of Layer 2 and Layer 1 of the OSI model – so it is very similar to wired networking • Install the wireless card (and drivers); set up WAP and generally you are good to go • WAPs have an integrated Web server and are configured through a browser-based setup utility

  18. Placing Access Points • Do a site survey – either yourself or contract • Use a laptop and look around your site for networks already there and to be avoided • Contract out the survey if multiple APs are needed • Can get Power-Over-Ethernet (PoE) APs if placement and power availability are issues

  19. Range Limiters • Cordless telephones • Large electrical appliances such as refrigerators • Baby monitors, microwave ovens • Fuse boxes, metal plumbing, metal studding and air conditioning units • Sun spots, really!

  20. Installing and Configuring • Ad hoc or infrastructure? • Take notes about how you set the AP so you can get correct settings on clients • Make sure device drivers are installed correctly • Follow required security guidelines • Skip 5 channels, if you can

  21. Antennae • Omni-directional or Dipole Antenna or Rubber Ducky – most common type • Figure 23-22 shows 2dB and 11dB antennae • Semidirectional for broadcast from corner of office shown in figure 23-21 • Highly directional for broadcast to one office • Cantennas are highly directional

  22. Troubleshooting Wi-Fi • Who is affected by the problem? • What is the nature of their network problem? • When did the problem start? • “Getting network address …” means password is wrong • If I possibly can do it, I will install a wired network • Low signal strength: move AP or client • Try a different channel: 1,6 or 11

  23. Troubleshooting, cont. • Check hardware: card seated correctly; device turned on, etc. • Check software: proper tools for configuration; skip firmware update unless really required • Move closer to AP or move AP closer to you

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