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Format of lecture. Introduction to Wireless Wireless standards Applications Hardware devices Performance issues Security issues. Wireless Technology. Wireless and mobile computing are the keywords Very topical/exciting This technology not yet mature

bree-gilbert
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Format of lecture

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  1. Format of lecture • Introduction to Wireless • Wireless standards • Applications • Hardware devices • Performance issues • Security issues

  2. Wireless Technology • Wireless and mobile computing are the keywords • Very topical/exciting • This technology not yet mature • Promises that we can improvise our existing networks without having to lay new wires - roving staff will just have to insert a wireless card into their device and join the network • Interesting to compare the what the Telco’s are doing with 3G and how this rivals WiFi hotspots

  3. Wireless Technology • Wireless technology has to compete with • digital satellite • Cable • phone lines (HomePNA) 10Mbps • Power line (HomePlug) 14Mbps • Wireless broadband technology (WiMax) gives wire-free transmission of two way multimedia • Bandwidth is an issue here

  4. Wireless Technology • What is on the market/coming? • Communication cards to allow data from personal digital assistants to be synchronised with desktop PC’s • Cards to link laptops and PC’s with Global System for Mobiles(GSM) based phones and local area network devices • All the above enables firms to set up wireless networks without having to use Ethernet cable

  5. Wireless Protocols • Wireless LAN • Bluetooth • WAP/GPRS/UMTS • SWAP - Shared Wireless Access Protocol • 3G - third generation cellular standard

  6. Wireless versus Wired networks • Using Radio frequency (2.4GHz and 5GHz) • Easy to setup a small office or home office (SOHO) • Mobility • Travel through wall • Easy for network reconstruction

  7. What is WiFi? • Wireless LAN IEEE 802.11x network • Promulgated by an association called WiFi Alliance • WiFi Alliance certifies all wireless LAN IEEE802.11x based products for interoperability • All IEEE802.11x based products that passed the WiFi Alliances are called WiFi • Wireless Fidelity

  8. WiFi Standards • IEEE 802.11a • An IEEE standard for a wireless network that operates at 5 GHz with rates up to 54Mbps • IEEE 802.11b • An IEEE standard for a wireless network that operates at 2.4 GHz with rates up to 11Mbps • IEEE 802.11g – referred to as 54g (but don’t confuse that with the 54Mbps!) • An IEEE standard for a wireless network that operates at 2.4 GHz with rates up to 54Mbps

  9. WiFi Standards • WPA (WiFi protected Access) • TKIP encryption and protects against unauthorized network access through the use of a pre-shared key (PSK) • WMM (WiFi MultiMedia) • packet prioritisation that meet IEEE 802.11e quality of service standard. • Packets containing time-dependent data such as audio or video to be sent ahead of data that can safely wait a few microseconds

  10. WiFi Hardware • Access points (APs) • PCMCIA cards/ PC cards • USB adapters • PCI network cards • Wireless routers

  11. WiFi Applications • Retails • Warehouses • Healthcare • Education • http://www.wifinetnews.com/ • News about wifi and also see if you can find out the hotspot(s) around the Stoke-on-Trent area

  12. WiFi topology • Ad Hoc • Without use of Access Point • Peer-to-peer style communication • Recommended 3 or less users per channel • Infrastructure • Communication each other devices by the use of Access Point • About 10-30 users per access point

  13. Ad Hoc vs Infrastructure • Ad Hoc can be setup instantly for temporary solution • Scalability is limited to Ad Hoc • Coverage • Reliability • Efficiency

  14. Wireless LAN

  15. Security choices • Network security ensures the communications and files are protected • How important of the security depend on how you want to use the network. • Browsing internet and mp3 streaming may not need a security • Internet shopping or purchasing will use SSL security • There are several way to protect your data confidentiality while transmitting • In WLAN, you can change your SSID, WEP or WPA or latest technology WPA2

  16. Wireless surfing • Common knowledge that some users use someone else’s network connection to use the Internet “piggybacking” • Hi-gain antenna example that I use • How do you know someone is using you? • If infrastructure – you don’t – would have to look at router logs • Ad-hoc – shows in connections window • How do they know you are not using them in return?

  17. WEP • Wired Equivalent Privacy • Encrypt data over the radio waves • Implemented in MAC layer – NIC encrypt the frame before transmit • Using 64bits or 128bits encryption keys • Shared secret key • You need to provide 40 bits (10 digit Hex) or 104bits (26 digit Hex) • 24 bits Initialisation Vector (IV) for generating key sequence

  18. Limitation of WEP • Share, static keys • WEP only encrypt frame within wireless station but not within wired network • Limited IV numbers and may increase collision - IV repeats after sending 26GB. • Recovery attack - the data can be manipulated after a few hours by tracking repeating IV

  19. WPA and WPA v2 • WiFi Protected Access • Different key for each user • 48 bit IV – defeats recovery attack on WEP • Use Temporal Key Integrity Protocol (TKIP) which dynamic change keys on transmission • More information on http://www.wifi.org

  20. Summary • Security is the main issues in wireless communications • Still in the development to increase the privacy • Next tutorial you will see wireless security in action

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