The BSSID is unique per SSID, per AP. The BSSID is usually derived (usually by incrementing the last octet) from the AP MAC address, however.
So an AP MAC might be 77:99:44:EE:C4:11.
It has a wireless network called "Bob's SSID". It will have a BSSID of something like 77:99:44:EE:C4:12.
Then, the AP may be broadcasting another called "Mary's SSID", and it will have a BSSID of something like 77:99:44:EE:C4:13.
Edit: More not-well-written info on BSSIDs: https://en.wikipedia.org/wiki/Service_set_(802.11_network)
Looks like the BSSID is derived from the AP serial number by some vendors. Never seen that myself.
The BSSID is unique per SSID, per AP. The BSSID is usually derived (usually by incrementing the last octet) from the AP MAC address, however.
So an AP MAC might be 77:99:44:EE:C4:11.
It has a wireless network called "Bob's SSID". It will have a BSSID of something like 77:99:44:EE:C4:12.
Then, the AP may be broadcasting another called "Mary's SSID", and it will have a BSSID of something like 77:99:44:EE:C4:13.
Edit: More not-well-written info on BSSIDs: https://en.wikipedia.org/wiki/Service_set_(802.11_network)
Looks like the BSSID is derived from the AP serial number by some vendors. Never seen that myself.