Bugzilla – Bug 398
NqstaWifiMac does not filter received frames by BSSID
Last modified: 2008-11-25 09:46:25 EST
Created attachment 286 [details]
The scenario is:
1- Two close Access Points
> Same channel
> Same SSID
> Different BSSIDs (MAC addresses)
2- Place a STA in the middle of the APs, so that it can perfectly receive signal from both the APs
3- Additionally make the APs send broadcast data frames
- The STA would associate with one of the APs and stick to it;
- The STA would only receive data frames from the AP to which it is associated
To support the above, I can quote some text from the standard, such as:
7.2.3 Management frames
A STA uses the contents of the Address 1 (DA) field to perform the address matching for receive decisions. In the case where the Address 1 (DA) field contains a group address and the frame type is other than Beacon, the BSSID also is validated to ensure that the broadcast or multicast originated from a STA in the BSS of which the receiving STA is a member.
7.2.2 Data frames
A STA uses the contents of the Address 1 field to perform address matching for receive decisions. In cases where the Address 1 field contains a group address, the BSSID also is validated to ensure that the broadcast or multicast originated from a STA in the BSS of which the receiving STA is a member.
What actually happens is:
-The STA continually tries to associate with both the APs; for each beacon received it tries to associate with that AP, regardless of already being associated to the other AP;
- The STA receives data frames from either AP, regardless of being associated with ir or not.
The attached patch fixes:
- BSSID filtering in beacons and data frames
- Don't receive data frames if not associated
- BSSID filtering in other management frames besides beacons;
this looks good.
gustavo, I think you can commit this patch yourself.