5.3 Given a scenario, deploy the appropriate wireless standard - Paiet/Tech-Journal-for-Everything GitHub Wiki

5.3 Given a scenario, deploy the appropriate wireless standard

  • 802.11a
    • 6,9,12,18,24,36,48,54Mbps
    • 5GHz
      • Not susceptible to interference like 2.4GHz
    • Dual band wireless NICs
      • Not true compatibility
      • NIC runs both standards
    • Uses the Orthogonal Frequency Division Multiplexing (OFDM)
    • Provides good throughput with poor distances
  • 802.11b
    • 1Mbps, 2Mbps, 5.5Mbps, and 11Mbps
    • 2.4GHz
    • At one time, the most deployed wireless standard
    • Employs CSMA/CA optionally
    • 802.11b uses Direct Sequence Spread Spectrum (DSSS) modulation
  • 802.11g
    • 54Mbps, 2.4GHz
    • Compatible with 802.11b
    • Inexpensive method for migrating from 802.11b
    • Mixed 802.11b/g environments
      • If all clients are on 802.11g except for 1, then everyone is forced to the 802.11b CSMA/CA standard
        • This is not the optimal network performance
      • Disable the 802.11b-ONLY mode on all APs
      • Modulation differences
        • 802.11b uses DSSS (Direct Sequence Spread Spectrum)
        • 802.11g uses Orthogonal Frequency Division Multiplexing (OFDM) which is more robust
          • 802.11g is the better standard, but any client that is forced to use the 802.11b standard loses that advantage
  • 802.11n
    • MIMO (Multi-Input, Multi-Output)
      • Uses multiple antennae for transmitting and receiving data at a higher rate
      • Can have up to 8 antennae
      • Typically only 4 antennae
      • Each antenna sends and receives part of the data splitting and rejoining the data at both the sending and receiving devices
        • Spatial Multiplexing
        • Supports up to 4 spatial streams
    • Operates on both the 2.4GHz and 5GHz spectrums
      • Gives the ability to control which spectrum is used, or both spectrums can be used
    • 40MHz channels
      • Doubles the size of 802.11a/g channels
      • Reclaims 11Mbps of unused bandwidth by not needing to protect the main carrier
      • Gives it a total of 119Mbps (54x2+11)
    • MAC efficiency
      • Speeds up data transfer by using a technique called Block Acknowledgement
        • Many packets can be passed before acknowledgement is required instead of requiring every packet be acknowledged
  • 802.11ac
    • 1Gbps, 5GHz
      • Realistically expect around 500Mbps
        • Still a reasonable choice for internal WLAN
    • Boasts 160MHz wide channels
      • Realistically 80MHz
        • Any interference found will reduce that to 40MHz and then down to 20MHz if interference is still found
    • MIMO
      • Supports up to 8 spatial streams
    • VHT (Very High Throughput)
      • Adds 4 fields to the wireless frame to identify it as VHT
      • 802.11a/g are only High Throughput