[PROPOSAL] Add hostapd.conf parameter to skip check forneighboring BSS (prevent fallback in 150Mb mode)

[Alex Vorona]

08.04.2012 12:35, Jouni Malinen wrote:

> On Sun, Mar 04, 2012 at 09:00:29AM +0200, Alex Vorona wrote:
>> Scan for neighboring BSSes prior to enabling 40 MHz channel [...] 40 MHz affected
>> channel range: [2422,2472] MHz Neighboring BSS: cc:96:a0:f5:4a:00 freq=2422 pri=3 sec=7
>> 40 MHz pri/sec mismatch with BSS cc:96:a0:f5:4a:00 <2422,2442> (chan=3+) vs.
>> <2457,2437> 20/40 MHz operation not permitted on channel pri=10 sec=6 based on
>> overlapping BSSes I can change channel to any between 1 and 10 in hostapd.conf and got
>> the same result. using HT40- instead HT40+ did not help. 
> Did you try using the same combination as the conflicting BSS, i.e., channel 3 HT40+? 
Yes, that worked but probably due to same channels I got 3-4MBytes/70ms  download/ping
instead of 10-11MBytes/20ms.

Here I go on channel 2 HT40+ - same as detected neighboring BSS
======================================
Received scan results (4 BSSes)
40 MHz affected channel range: [2402,2452] MHz
Neighboring BSS: cc:96:a0:f5:4a:01 freq=2417 pri=2 sec=6
Neighboring BSS: cc:96:a0:f5:4a:02 freq=2417 pri=2 sec=6
Neighboring BSS: cc:96:a0:f5:4a:03 freq=2417 pri=2 sec=6
Neighboring BSS: cc:96:a0:f5:4a:00 freq=2417 pri=2 sec=6
Completing interface initialization
Mode: IEEE 802.11g  Channel: 2  Frequency: 2417 MHz
[...]
iw wlan0 station dump
[...]
        tx bitrate:     150.0 MBit/s MCS 7 40Mhz short GI
voron at jdi:~$ wget -O /dev/null .../128m.jpg
[...]
2012-04-10 21:55:10 (3,72 MB/s) - ?/dev/null? saved [134217728/134217728]
======================================
Here I go on channel 10 HT40- with forced 40MHz
======================================
Received scan results (4 BSSes)
40 MHz affected channel range: [2422,2472] MHz
Neighboring BSS: cc:96:a0:f5:4a:00 freq=2417 pri=2 sec=6
40 MHz pri/sec mismatch with BSS cc:96:a0:f5:4a:00 <2417,2437> (chan=2+) vs. <2457,2437>
Completing interface initialization
Mode: IEEE 802.11g  Channel: 10  Frequency: 2457 MHz
[...]
iw wlan0 station dump
[...]
        tx bitrate:     150.0 MBit/s MCS 7 40Mhz short GI

voron at jdi:~$ wget -O /dev/null .../128m.jpg
[...]
2012-04-10 21:57:16 (10,1 MB/s) - ?/dev/null? saved [134217728/134217728]
======================================

> The only rule that hostapd is currently using for 40 MHz channels on 2.4 GHz band is to
> mandate that the same pri/sec channels are used with any other 40 MHz BSS in the
> affected frequency range.
So I had to watch to neighbors' APs channels every time my hostapd is started/restarted
and change channel/HT40+/- in hostapd.conf?  Ok, and if there will be two 40MHz APs before
my hostapd? And neighbors' APs will dynamically(or on boot) change their channels?

> If there is more than one 40 MHz BSS on 2.4 GHz already running with conflicting
> channels, they should not really have started in the first place.. Is that the case here? 
I think these APs do not care about neighbors. They care about their owners, housewifes,so
they just up and run @40MHz despite of anything.

Regards,
Alex


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