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SSID/BSSID/BSS and SSID hiding

SSID(service set identifier) ASSCI string:
A series of 0 to 32 octets, Network name, Unique identifier for a wireless LAN.

BSS(Basis service set):
a single AP together with all associated clients(STAs) is called a BSS. Each BSS is uniquely identified by a basic service set identification (BSSID)

BSSID(Basis service set identifier):
the BSSID is the MAC address of the  AP generated by combining the 24 bit Organization Unique Identifier (the manufacturer's identity) and the manufacturer's assigned 24-bit identifier.

ESS(Extended Service set):
each BSS still has its BSSID, however, the entire ESS uses only one SSID ( to facilitate roaming), BSSID is a locally administered MAC address generated from a 48-bit random number.

Hiding SSID:

AP will not broadcast the SSID, this feature is to prevent unauthorized users from being able to detect the wireless network from their wireless clients. APs send beacon frames to advertise capability information and parameter sets for the network. Turning off broadcasting on the AP does not prevent the beacon frame from being sent. The wireless AP still sends a beacon frame, but it is sent with the SSID value set to NULL.
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