toggle short / long preamble with hostapd

[Sam Leffler]

Sin wrote:
> Hello,
> 
> 
> Does anyone know how to enable short preamble in 7-STABLE ?
> 
> I'm using ath with hostapd in ap mode.  It seems there was an option in hostapd.conf, but this is not in FreeBSD's /usr/share/examples/hostapd/hostapd.conf
> 
> 
> The missing hostapd.conf option was found in google:
> 
> # Short Preamble
> # This parameter can be used to enable optional use of short preamble for
> # frames sent at 2 Mbps, 5.5 Mbps, and 11 Mbps to improve network performance.
> # This applies only to IEEE 802.11b-compatible networks and this should only be
> # enabled if the local hardware supports use of short preamble. If any of the
> # associated STAs do not support short preamble, use of short preamble will be
> # disabled (and enabled when such STAs disassociate) dynamically.
> # 0 = do not allow use of short preamble (default)
> # 1 = allow use of short preamble
> #preamble=1
> 
> 
> my version of hostapd is " v0.5.10 " - I was not able to set this option

On freebsd hostapd is _purely_ an authenticator; to configure 802.11 
parameters you use ifconfig.

> 
> 
> hostapd.conf:
> 
> interface=ath0
> #preamble=1
> debug=1
> ctrl_interface=/var/run/hostapd
> ctrl_interface_group=wheel
> ssid=private
> wpa=1
> wpa_passphrase=apassword
> wpa_key_mgmt=WPA-PSK
> wpa_pairwise=TKIP
> 
> 
> 
> rc.conf:
> 
> hostapd_enable="YES"
> ifconfig_ath0="mode 11g hidessid mediaopt hostap"
> 
> 
> 
> ifconfig ath0:
> 
> ath0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
>         ether 00:17:9a:4c:e7:83
>         media: IEEE 802.11 Wireless Ethernet autoselect mode 11g <hostap>
>         status: associated
>         ssid private channel 1 (2412 Mhz 11g) bssid 00:17:9a:4c:e7:83
>         authmode WPA privacy MIXED deftxkey 2 TKIP 2:128-bit TKIP 3:128-bit
>         txpower 31.5 scanvalid 60 bgscan bgscanintvl 300 bgscanidle 250
>         roam:rssi11g 7 roam:rate11g 5 protmode CTS burst hidessid dtimperiod 1

In ap mode you should not manually configure preamble; it should be 
selected according to the associated stations.  What are you trying to 
accomplish?

	Sam