Configuring WiFi Network Roaming


Issue

Different wireless network instances have been configured for a mobile thin client. The thin client should switch over to the strongest network automatically.


Solution

Parameters to configure WiFi roaming options can be found in the IGEL registry (Setup > System > Registry). These settings should be changed by experts only.

  • Parameters for better control of WiFi roaming capabilities with access points that share the same SSID:
    network.interfaces.wirelesslan.device0.lock_initial
    Default: false
    If true the device will stick to the access point it is connected to even if candidates with better signal quality are present.
    Setting this parameter to true is a last resort for problems that are caused by too much roaming.
    network.interfaces.wirelesslan.device0.bgscan.module
    Only active with encryption methods WPA Enterprise and WPA2 Enterprise.
    Default: none
    Possible values:
    none : No background scanning is done.
    simple : The WiFi module tries to scan for a potentially better signal in the background.
    bgscan.modulesimple provides following options:
    network.interfaces.wirelesslan.device0.bgscan.simple.signal_strength (default: -45 dBm)
    This defines a threshold that determines which of the following two parameters shall be effective.
    network.interfaces.wirelesslan.device0.bgscan.simple.short_interval (default: 30 s)
    Interval between background scans (in seconds) if the actual signal level of the currently connected access point is worse than signal_strength.
    network.interfaces.wirelesslan.device0.bgscan.simple.long_interval (default: 300 s)
    Interval between background scans (in seconds) if the actual signal level of the currently connected access point is better than signal_strength.

    If parameter lock_initial is true, it is recommended to set bgscan.module to none.
  • Parameters to control WiFi roaming between WiFi networks with different SSIDs:
    network.interfaces.wirelesslan.device0.mssid_check_interval (default: 10 s)
    The interval in seconds between checking if automatic roaming might be neccessary.
    This includes detecting that a connection has been lost and a new one should be established.
    network.interfaces.wirelesslan.device0.mssid_quality_threshold (default: 20)
    If the current connection's quality percentage is below this value
    scanning will be performed to find a potentially better network.
    network.interfaces.wirelesslan.device0.mssid_quality_difference_threshold (default: 40)
    A candidate for automatic roaming is only considered if its quality percentage
    is this much better than the current connection's quality.
    network.interfaces.wirelesslan.device0.mssid_previously_used_threshold (default: 55)
    During boot: If the previously used SSID's quality percentage is above this threshold it is preferred.
    network.interfaces.wirelesslan.device0.mssid_user_selection (default: false)
    If true, the user can initiate roaming to a network via the WiFi tray icon's context menu (must be enabled).
    If automatic roaming shall not interfere with the user's choice, the following values are appropriate:
    network.interfaces.wirelesslan.device0.mssid_quality_threshold = 0
    network.interfaces.wirelesslan.device0.mssid_quality_difference_threshold = 101
    network.interfaces.wirelesslan.device0.mssid_previously_used_threshold = 0

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Last update: June 28, 2018