When set to operate in Roaming mode, the VAC can roam seamlessly among Access Points (APs) sharing the same SSID and the same security configuration without interrupting its IP connectivity. The VAC has a monitoring mechanism that is sensitive to drops in AP signal strength. When the VAC detects such a drop (<= WSRL threshold), it automatically starts searching for APs in its vicinity that have a stronger signal (>= WSRH threshold), while remaining connected to the current AP. It attempts to connect to the AP that appears first on the list of assigned SSIDs, while remaining connected to the current AP. If association with the new AP fails, the VAC continues scanning until it succeeds connecting to an AP with a stronger signal. When in Roaming mode, the VAC does not restart its DHCP client process for new connections.
The VAC periodically confirms the BSSID it is connected to - even if it maintains its IP connection while in roaming mode - and reports the current BSSID to the PowerFleet system as part of its Wi-Fi location algorithm.
Configurable Parameters:
Syntax: AT+iWSRL=n [n = 0-254]
· Sets a low SNR threshold for Roaming mode. If the SNR value of the signal from the AP the VAC is currently associated with drops below n, it is considered a low SNR event. Parameters: n=0-254 dB Default: n=10 dB (if not specified); IDSY default: 15
Syntax: AT+iWSRH=n [n = 10-255]
· Sets a high SNR threshold for Roaming mode. The VAC will re-associate only with APs having SNR that is better than n. Parameters: n=0-254 dB Default: n=30 dB (if not specified); IDSY default: 25