WIRELESS Networks

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WIRELESSNetworks
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Wireless networks

• Comfortable
• Informality
• No cables
• Leaking information
• SSID Broadcasting

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WLAN topologies

• Ad-Hoc
• Infrastructured method topology

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• Ad-Hoc

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Ad-Hoc

• Casual network
• All computers are clients and hosts too
• Low transfer speed
• Bad security
• Compatibility problems

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Infrastructured method topology

• Prevention of compatibility problems
• Create acces points
• Connect with cable to the wired LAN
• Masked area cell

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• Infrastructured method topology

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WLAN tools

• Wireless network card
• Simple wireless card (Desktop computers)
• PCMCIA card (Laptops)
• External USB wireless key
• Integrated card
• Acces point

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Technological properties

• The electro-magnetic indications
• Extend to straight
• Longer distance -gt lower intensity
• Reflections interference

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Modulation procedures

• AM Amplitude modulated
• FM Frequency modulated
• PM Period Modulated

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Modulation procedures
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Wireless Ethernet technologies

• IEEE 802.11
• IEEE 802.11 a
• IEEE 802.11 b
• IEEE 802.11 g

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IEEE 802.11

• 2,4 GHz frequency range
• 1-2 Mbit/s transfer-rate
• DSSS - Direct Sequence Spread Spectrum
• FHSS - Frequency Hopping Spread Spectrum

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IEEE 802.11 b

• 2,4 GHz frequency range
• 1 2 5,5 11
• HR-DSSS Wi-FiTM
• Compatible with older technologies

Mbit/s transfer-rate
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IEEE 802.11 a

• 5 GHz frequency range
• 54 Mbit/s transfer-rate
• With data duplication 108 Mbit/s
• 52 used frequency
• Not fully compatible with other technologies

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IEEE 802.11 g

• 2,4 Ghz ISM band
• 54-108 Mbit/s transfer-rate
• Modulation procedure OFDM
• Fully compatible with older technologies
• This is the most used technology

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WLAN security

• Disable the SSID Broadcasting
• Network identifier (MAC) filter
• Use data encryption
• Opened WLAN

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War Spamming

• Less defended Acces Points
• Mailing system
• Unbidden mails Spam
• Hard to protect

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Data Encryption Standards

• WEP Wired Equivalent Privacy
• WPA Wi-Fi Protected Access
• IEEE 802.11Tgi - WPA2

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WEP

• RC4 procedure
• 40 or 104 bit keys
• Static keys
• Key changer protokolls
• 24 bit Initialize Vectors - IV

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WPA

• Fix WEPs disadventages
• 48 bit IV
• TKIP Temporal Key Integrity Protocol
• AES - Advanced Encryption Standard
• 8 bit MIC Message Integrity Code
• WPA and WEP can used together

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IEEE 802.11Tgi

• IEEE Taskgroup i
• AES Advanced Encryption Standard
• 128-256 bit keys
• The most up-to-date technology
• Compatible with WPA protokolls

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War Driving

• Car
• Antenna
• Laptop
• Route
• Freetime

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Statistics

• From 100 WLAN
• 55 opened ( 5 original SSID )
• 25 WEP/WPA
• 20 WPA2
• Un-official datas

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End