Metageek: InSSIDer and Chanalyzer

Notes:
  • Includes neighboring networks on same channel
  • Only one device can talk at the same time on the same channel
  • Like a 4-year old; will repeat until acknowledged
Notes:
  • Lower frequencies can pass through ‘stuff’ better than higher frequencies
Notes:
  • 5 MHz of space between channels on 2.4 GHz
  • Only three channels that don’t overlap (1, 6, 11)
Co-Channel interference:
  • Compare to number of people at dinner table - politely speaking
  • More people, less opportunity to talk
  • Too many devices
Adjacent Channel Interference
  • Dinner table at a restaurant - but you’re not the only ones
  • People yelling and screaming over each other
  • Noisy restaurant; ask people (i.e. devices) to repeat themselves
  • Result is slower performance
  • Ideal: If everyone only used 1, 6 and 11 that would eliminate adjacent channel interference
Wi-fi scanning:
  • Doesn’t show how busy the channel is
  • Also can’t see interference from non-wifi devices
Spectrum analysis gives a lot more information
Notes:
  • Remember only one device can speak at a time per channel
  • Non-Wifi interference spits out garbage and interferes with polite devices on network
  • Devices will not have time to talk