Question : 802.11ac - channel & config

Tue Jun 24 05:05:49 PDT 2014

2014-06-24 10:04 GMT+02:00 Charles Moulliard <ch007m at gmail.com>:
> Thx Janusz for your reply and your help.
>
> Here is more info collected based on your input. I have created a gist
> ticket with hostapd config, result to run the command 'iw list' and what is
> displayed in debug mode by hostapd -->
> https://gist.github.com/cmoulliard/17eba8ed42b81afb064d
>
> Remark : The new config does not work now and I don't get an error in the
> log
>

           * 5230 MHz [46] (20.0 dBm) (passive scanning, no IBSS)
            * 5240 MHz [48] (20.0 dBm)
            * 5260 MHz [52] (20.0 dBm) (passive scanning, no IBSS,
radar detection)

Seems using your HW you can setup AP only on channel 48 and only with
VHT20 - such HW limitation (btw you have old iw).
Seems DFS is also not supported.

Change your config file:
#ieee80211h=1
#ieee80211d=1

ht_capab=[SHORT-GI-20]
vht_oper_chwidth=0
vht_oper_centr_freq_seg0_idx=48

You should get VHT20, with your 2 spacial streams you will have max tp
about 173Mbps (20MHz width and 2 spacial streams and SGI) - for 80211n
that was 144,4Mbps.

To be sure connected station will use ht you can setup:
require_ht=1

> Regards,
>
>
>
> On Tue, Jun 24, 2014 at 9:18 AM, Janusz Dziedzic <janusz.dziedzic at tieto.com>
> wrote:
>>
>> On 23 June 2014 13:09, Charles Moulliard <ch007m at gmail.com> wrote:
>> > Hi,
>> >
>> > Something goes wrong with my config of hostapd 2.2 on a linux kernel
>> > (3.14.7-200.fc20.x86_64). I have plugged an Edmix AC200 (WIFI USB) and
>> > it
>> > works fine using this driver
>> > (https://github.com/abperiasamy/rtl8812AU_8821AU_linux) and setup
>> > (hostapd
>> > 2.2 + dnsmaq) but I can't change the channel to a value higher than 48
>> > and
>> > bitrate is around 24Mbits/s (measured with iperf) between this machine
>> > and a
>> > client (=MacBook pro)
>> >
>> > What is the issue ?
>> >
>> 64 - is DFS channel, so required HW that support radar detection +
>> hostap config (country_code=, ieee80211d=1, ieee80211h=1)
>>
>> > sudo ./hostapd config_test.conf
>> > Configuration file: config_test.conf
>> > wlp0s20u2: IEEE 802.11 Configured channel (64) not found from the
>> > channel
>> > list of current mode (2) IEEE 802.11a
>> > wlp0s20u2: IEEE 802.11 Hardware does not support configured channel
>> > Could not select hw_mode and channel. (-3)
>> >
>> > More debug output available here :
>> > https://gist.github.com/cmoulliard/81aa9c7dc60c366f4724
>> >
>> > iwlist wlp0s20u2 channel
>> > wlp0s20u2  32 channels in total; available frequencies :
>> >           Channel 01 : 2.412 GHz
>> >           Channel 02 : 2.417 GHz
>> >           Channel 03 : 2.422 GHz
>> >           Channel 04 : 2.427 GHz
>> >           Channel 05 : 2.432 GHz
>> >           Channel 06 : 2.437 GHz
>> >           Channel 07 : 2.442 GHz
>> >           Channel 08 : 2.447 GHz
>> >           Channel 09 : 2.452 GHz
>> >           Channel 10 : 2.457 GHz
>> >           Channel 11 : 2.462 GHz
>> >           Channel 12 : 2.467 GHz
>> >           Channel 13 : 2.472 GHz
>> >           Channel 36 : 5.18 GHz
>> >           Channel 40 : 5.2 GHz
>> >           Channel 44 : 5.22 GHz
>> >           Channel 48 : 5.24 GHz
>> >           Channel 52 : 5.26 GHz
>> >           Channel 56 : 5.28 GHz
>> >           Channel 60 : 5.3 GHz
>> >           Channel 64 : 5.32 GHz
>> >           Channel 100 : 5.5 GHz
>> >           Channel 104 : 5.52 GHz
>> >           Channel 108 : 5.54 GHz
>> >           Channel 112 : 5.56 GHz
>> >           Channel 116 : 5.58 GHz
>> >           Channel 120 : 5.6 GHz
>> >           Channel 124 : 5.62 GHz
>> >           Channel 128 : 5.64 GHz
>> >           Channel 132 : 5.66 GHz
>> >           Channel 136 : 5.68 GHz
>> >           Channel 140 : 5.7 GHz
>> >           Current Frequency:5.24 GHz (Channel 48)
>> >
>> Please use iw list instead.
>>
>> > dabou at localhost Temp$ iwconfig
>> >
>> > wlp0s20u2  IEEE 802.11a  ESSID:"fuselab"  Nickname:"<WIFI at REALTEK>"
>> >           Mode:Master  Frequency:5.24 GHz  Access Point:
>> > D8:50:E6:F3:96:C7
>> >           Bit Rate:54 Mb/s   Sensitivity:0/0
>> >           Retry:off   RTS thr:off   Fragment thr:off
>> >           Power Management:off
>> >           Link Quality=66/100  Signal level=48/100  Noise level=0/100
>> >           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>> >           Tx excessive retries:0  Invalid misc:0   Missed beacon:0
>> >
>> > Config used :
>> >
>> > interface=wlp0s20u2
>> > ssid=fuselab
>> > #channel=48
>> > channel=64
>> >
>> > # WPA and WPA2 configuration
>> > macaddr_acl=0
>> > auth_algs=1
>> > ignore_broadcast_ssid=0
>> > wpa=3
>> > wpa_passphrase=fuselab987
>> > wpa_key_mgmt=WPA-PSK
>> > wpa_pairwise=TKIP
>> > rsn_pairwise=CCMP
>> >
>> > # Hardware configuration
>> > driver=nl80211
>> > wme_enabled=1
>> > ieee80211n=0
>> > ieee80211ac=1
>> > hw_mode=a
>> >
>> Here you can use (v)ht40/vht80 - as I remember correctly 80211ac=1
>> required also 80211n=1.
>>
>> BR
>> Janusz
>
>
>
>
> --
> Charles Moulliard
> Apache Committer / Architect @RedHat
> Twitter : @cmoulliard | Blog :  http://cmoulliard.github.io
>
>
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-- 
Janusz Dziedzic