Dynamically loading/unloading BSS

[Heming Wen]

Hello,

I am interested in dynamically adding/removing secondary BSS'es on a radio interface controlled through hostapd.

I modified the source code of hostapd to include some new functions to add and remove a BSS to a radio interface without the need to 
restart the entire radio interface. I am using the nl80211 driver. The dynamic adding part works very well. However, when I remove a BSS, 
the other BSS on the same radio interface will stop broadcasting the beacon frames. The other BSS still responds to probe request and can perform 
authentication. A client station connected to the BSS retains the connection and can still connect to the network. On the other hand. if I add a new BSS again, the beacon broadcast will resume.

The adding BSS function eventually calls hostapd_setup_bss() while the remove BSS function calls if_remove(). It seems the if_remove function 
call to the nl80211 driver stops the beacon broadcast for all of the BSS of the radio interface and not just the specified BSS. Is this an expected 
behavior?

Note: This is a follow-up question related to another thread:
http://lists.shmoo.com/pipermail/hostap/2013-July/028197.html

Thank you,
Heming