[ath9k-devel] What are [SHORT-GI-40] and [DSSS_CCK-40] good for?

[Tamas Selmeci <tselmeci@dension.com>]

Hi all!

I have an AR5416-based TP-Link miniPCI wifi card. To be honest, I'm far 
away from being satisfied with it's transfer speed, but it doesn't seem 
to be the fault of the driver.

Trying to optimize performance in AP mode, hostapd provided the 
following ht_capab options (supported by the chip, of course):
[HT40+], [HT40-]: ok, no problem.

[SHORT-GI-40], [DSSS_CCK-40]: I don't know them. When these flags were 
set and the AP was running on channel 8 or 10, the client with an 
TP-Link AR9170 USB dongle (Windows) failed to connect to it. It started 
the connection but failed almost always getting an IP from DHCP server. 
So these flags are now not set, and the situation seems to be rather good.

Could you please tell me in a few words what should these two unknown 
options cause?

iwconfig wlan0 power off is performed.
hostapd.conf now:

interface=wlan0
driver=nl80211
ieee80211n=1
hw_mode=g
max_num_sta=256
ht_capab=[HT40+]
channel=2
tx_queue_data3_aifs=7
tx_queue_data3_cwmin=15
tx_queue_data3_cwmax=1023
tx_queue_data3_burst=0
tx_queue_data2_aifs=3
tx_queue_data2_cwmin=15
tx_queue_data2_cwmax=63
tx_queue_data2_burst=0
tx_queue_data1_aifs=1
tx_queue_data1_cwmin=7
tx_queue_data1_cwmax=15
tx_queue_data1_burst=3.0
tx_queue_data0_aifs=1
tx_queue_data0_cwmin=3
tx_queue_data0_cwmax=7
tx_queue_data0_burst=1.5
logger_syslog=1
logger_syslog_level=0
logger_stdout=-1
logger_stdout_level=0
debug=1
ctrl_interface_group=0
macaddr_acl=0
auth_algs=1
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ssid=apname
wpa=3
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP
rsn_pairwise=CCMP
ap_max_inactivity=15
wpa_psk=47a8cf2591b8ad8726514fff464a315678ecd72c0f920d7a92dcdca8c32f6107

Thanks,

Regards,
-- 
Tamas Selmeci
R&D Engineer