On MacOS/X, to see the BSSID of the wireless base station you’re connected to, hold down [Option] while clicking on the WiFi icon on the top.
If you want MacOS/X to automatically roam between wireless bridges with the same SSID, they all must have the exact same wireless security configured, so if one is set for WPA2 Personal and another is set for WPA/WPA2 mixed modes, your laptop will NOT roam automatically between them.
Apple advises NOT to use different SSIDs for your bridges’ different bands (2.4GHz, 5GHz, etc.) Some people advise otherwise.
Monitor with NetSpot:
https://www.netspotapp.com/download-mac.html
References: