Wireless Access

Hi Everyone,

 

I would like to know how BSSID is calculated based on the AP MAC address?

 

Are the calculations vary depends on the radio interface of the AP?

 

If anyone explains with the full calculation in detail then it will be really helpful.

 

Thanks in advance.

Somebody provided this to me awhile ago

 

First Step:
The controller takes the OUI and simply uses it as the first 6 characters of the BSSID 00:0b:86:

 

Second Step:
This is the interesting part. The controller first takes the next character and simply removes it.  6
The next character is then taken  6
A Boolean XOR is performed using this character and the value Hex 8, creating a new character  E

 

Third Step:
At this point the controller takes the next 3 HEX characters from the MAC address (characters 9-11)  0:da:
These 3 characters are appended to the first 7 characters, and these are the first 10 characters of the BSSID 00:0b:86:E0:da:

 

Fourth Step:
If the AP has 2 Ethernet ports and 2 Radios, then each Radio will be capable of a total of 16 BSSIDs
The 2.4 GHz radio will use the last HEX character of the wired Ethernet port for it's 11th character  3
The 2.4 GHz radio will begin assigning HEX values starting at 0 and incrementing to F for the 12th and final character 00:0b:86:E0:da:30 through 00:0b:86:E0:da:3F
The 5 GHz radio will increment the last HEX character of the wired Ethernet port by 1, and use it for it's 11th character 4
The 5 GHz radio will begin assigning HEX values starting at 0 and incrementing to F for the 12th and final character 00:0b:86:E0:da:40 through 00:0b:86:E0:da:4F

Added an example calculation here.

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Herman Robers
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Original Message:
Sent: Jan 27, 2014 10:26 PM
From: Victor Fabian
Subject: BSSID for the SSID

Somebody provided this to me awhile ago

 

First Step:
The controller takes the OUI and simply uses it as the first 6 characters of the BSSID 00:0b:86:

 

Second Step:
This is the interesting part. The controller first takes the next character and simply removes it.  6
The next character is then taken  6
A Boolean XOR is performed using this character and the value Hex 8, creating a new character  E

 

Third Step:
At this point the controller takes the next 3 HEX characters from the MAC address (characters 9-11)  0:da:
These 3 characters are appended to the first 7 characters, and these are the first 10 characters of the BSSID 00:0b:86:E0:da:

 

Fourth Step:
If the AP has 2 Ethernet ports and 2 Radios, then each Radio will be capable of a total of 16 BSSIDs
The 2.4 GHz radio will use the last HEX character of the wired Ethernet port for it's 11th character  3
The 2.4 GHz radio will begin assigning HEX values starting at 0 and incrementing to F for the 12th and final character 00:0b:86:E0:da:30 through 00:0b:86:E0:da:3F
The 5 GHz radio will increment the last HEX character of the wired Ethernet port by 1, and use it for it's 11th character 4
The 5 GHz radio will begin assigning HEX values starting at 0 and incrementing to F for the 12th and final character 00:0b:86:E0:da:40 through 00:0b:86:E0:da:4F