4.3 Given a scenario, troubleshoot and resolve common wireless issues - Paiet/Tech-Journal-for-Everything GitHub Wiki

4.3 Given a scenario, troubleshoot and resolve common wireless issues

  • Signal loss (Attenuation)
    • Frequency Increase
    • Range Increase
    • The farther you are away from an access point the more the signal will degrade and transmission speeds will go down
    • Bring the client closer to the access point
    • Bring the access point closer to the client
      • Place the AP in a more optimal area
    • Add access point at the edge of network wireless range
    • RF Interference
    • Interference comes from devices that are sharing the wireless radio frequencies or naturally disperses RF
      • Cordless phones
      • Microwaves
      • Garage door openers
      • Metal walls, buildings
    • Use a wireless analyzer to look for lowest signal to noise ratio areas for optimal AP placement
    • Remove or move devices that cause interference
    • Wireless Router
    • Wireless NIC
      • Power Management
  • Interference
    • EFI
    • RF
  • Overlapping channels
    • Mismatched channels
  • Signal-to-noise ratio
    • Compares the wireless signal to the background noise
    • The greater the differentiation the better signal
    • 41dB or higher is ideal, 25 - 40dB is good, 16 - 24dB is poor, and 10 - 15 db is unreliable.
  • Device saturation
    • Device are only cable of a limited amount of connections
    • More than this limit, performance degradation is high
  • Bandwidth saturation
    • e.g. 54 Mbps on 802.11g. If 10 users, 5.4 Mbps per user because it is a SHARED 54 Mbps connection
  • Untested updates
    • some untested updates can cause issues, you may want to wait for an update from the manufacturer rather than a 3rd party update.
  • Wrong SSID
    • User's could be connected to another Wireless AP rather than the one for your company.
  • Power levels
    • Distance
    • Signal Strength
  • Open networks
  • Rogue access point
  • Wrong antenna type
    • Omni-Directional
    • Yagi
  • Incompatibilities
    • In theory, this isn't supposed to happen due the 802.11 standardization.
    • Manufacturers differ though in underlying technology that may not be compatible with other manufacturers.
  • Wrong encryption
    • Must match on client and AP
  • Bounce
    • repeaters and reflectors help extend the signal
    • as signal "bounces" signal off of objects the signal could becomes a multipath signal arriving at the destination multiple times.
    • Some APs can sample multiple path signal and drop the weaker.
    • Some 802.11n can combine all mutlipath signals to increase the distance from the AP.
  • MIMO (Multiple In/Multiple Out)
    • 802.11n technology that can send multiple signals and receive mutliple signals simultaneously.
  • AP placement
    • as centrally located as possible for you coverage area.
  • AP configurations
    • LWAPP (Light Weight Access Point Protocol)
    • Thin vs thick
      • AP is configured to receive security and configuration from controller (Thin)
      • AP is autonomous
  • Environmental factors
    • Concrete walls
    • Window film
    • Metal studs
  • Wireless standard related issues
    • Throughput
    • Frequency
    • Distance
    • Channels