Hi community,
This email is mainly addressed to hostap/wpa_supplicant mailing list.
Descriptions of my issue: - I am establishing IBSS/adhoc network using OpenWRT 15.05 + ath9k (AR9331). - When nodes are relatively closely placed, the peers (the term is 'neighbors' in batman-adv mesh) reach 40, ath9k driver detects "tx hung, resetting the chip" (for RESET_TYPE_TX_HANG). - This ath9k "tx hung" randomly happens among the 40 nodes (in adhoc network), and it happens relatively often (seemingly randomly for nodes), and randomly makes some nodes un-usable. - This appears to be an issue with ath9k kernel driver or ath9k hardware that it can not handle ~40 peers. - IBSS/adhoc with 20 peers work well.
Is there a config in wpa_supplicant that we can limit the number of peers?
In the other words, once the number of peers ('iw wlan0 station dump') reaches a pre-configured number (e.g. 12 or 16), wpa_supplicant does not authenticate any more, for IBSS/adhoc only? - A subtle detail: once a new beacon with higher RSSI is detected, the current connection with lowest RSSI will be de-authenticated, and to authenticate this new peer (with higher RSSI in beacon).
Is this "limiting number of peers for IBSS/adhoc" a good work-around for 40+ peers adhoc network, although the ultimate root cause seemingly is with ath9k kernel driver or ath9k hardware?
Also, if there are many (like 40+) peers in IBSS/adhoc network, I am not sure how medium access contention and collisions factor in, for management frames?
Here is my wpa_supplicant conf file: ------ ctrl_interface=/var/run/wpa_supplicant
# use 'ap_scan=2' on all devices connected to the network # this is unnecessary if you only want the network to be created when no other networks are available ap_scan=2
network={ ssid="Net-xxxxxxxx" mode=1 frequency=2462 proto=WPA2 key_mgmt=WPA-PSK pairwise=CCMP group=CCMP psk="xxxxxxxx" } ------
Another approach could be to use user-space shell script to "iw <dev> ibss leave" for the lower RSSI stations? - As I am using batman-adv to build mesh network on the top of IBSS/adhoc, a similar approach can be done at batman-adv level.
Suggestions?
Thanks. Xuebing Wang