How to Configure Wi-Fi Network Roaming

Issue

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

Solution

Parameters to configure Wi-Fi 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 Wi-Fi 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
  Default: default (Perserving the unpachted NM's behaviour)
  Possible values:
  default : No background scanning is done.
  simple : The Wi-Fi module tries to scan for a potentially better signal in the background.
  
  bgscan.module simple 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 Wi-Fi roaming between Wi-Fi 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 Wi-Fi 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