HandsOn Exercises: IEEE 802'11b Standard

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Hands-On ExercisesIEEE 802.11b Standard

• Mohammad Hossein Manshaei
• hossein.manshaei_at_epfl.ch
• Feb. 2009

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Hands-On Exercises IEEE 802.11b

• IEEE 802.11 Infrastructure Mode
• Security of IEEE 802.11
• IEEE 802.11 Ad Hoc mode
• Routing in Ad-Hoc networks

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Introduction to IEEE 802.11 MAC Layer

• MAC is Polling or Distributed Coordination
  Function
• Distributed Coordination Function (DCF) which
  is CSMA/CA based
• Optional RTS/CTS packets to avoid hidden node
  problem

• In this HoE, we evaluate the performance of DCF
  without RTS/CTS

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Introduction to IEEE 802.11 Physical Layer
Frequency
902 MHz
928 MHz
2.4 GHz
2.4835 GHz
5.725 GHz
5.785 GHz
Cordless Phones
1997 802.11 Legacy 1 2 Mbps Over-the-Air
Modulation DSSS, FH, IR (DBPSK and DQPSK)
1999 802.11a 6 to 54 Mbps OFDM (BPSK, QPSK,
16-QAM, 64-QAM)
1999 802.11b 1 2 5.5 11 Mbps CCK Modulation
2003 802.11g 1 to 54 Mbps

• Future is for 802.11n with up to 540 Mbps at
  application layer

Time
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1. Infrastructure Mode
SSID iew IP 192.168.1.1

• Configuration
• We use RutilT to configure the adapters
• DHCP for address allocation
• No difference between routers and stations

Router
Router
Station
Station
192.168.1.100
192.168.1.143
192.168.1.127
192.168.1.118
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1. Infrastructure Mode

• FTP with wire and wireless server
• wireshark tool
• Throughput evaluation with iptraf

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2. Security of IEEE 802.11

• Example of vulnerability Password sniffing over
  ftp connection

SSID iew IP 192.168.1.1
192.168.1.127
192.168.1.227
Password sniffing by laptop in monitor mode or
any other stations
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3. Ad Hoc Mode

• Ad Hoc configuration using RutilT and evaluate
  the throughput
• Fairness issues (running two FTP connections for
  two Ad Hoc networks)

FTP1
10.0.0.1
10.0.0.2
FTP2
10.0.0.3
10.0.0.4
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4. Routing in Ad Hoc Networks (AODV)

• Ad Hoc Configuration using RutilT
• Use the iptables to make virtual coverage range
• Running AODV and trace the routes for 2 or 3
  hops
• Evaluate the throughput

10.0.0.3
10.0.0.4
10.0.0.2
10.0.0.1
FTP Connection
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HoE Organization

• Please send an email, today after 5pm to
• mobnet.epfl_at_gmail.com
• With subject
• Group 1 ? If you prefer participating in the
  first session on March 4th (1315 to 1600)
• Group 2 ? If you prefer participating in the
  second session on March 4th (1615 to 1900)

We will try to accommodate your preference, with
FCFS priority if needed.The list of participants
will be posted at mobnet.epfl.ch on March 2nd
(Monday).