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5 GHz DFS channels

Posted: Thu Mar 24, 2016 11:09 am
by n8b
In Connection | Basic | Wireless. Dropdown "Wireless Channel (5GHz)"

A) How about marking DFS channels, and make a "more info" link explaining DFS?

Example for EU:
36
40
44
48
52 (DFS)
56 (DFS)
and so on.

And info like:
"Dynamic Frequency Selection (DFS) means the channel might change automatically to another 5 GHz channel to avoid radar interference."

https://en.wikipedia.org/wiki/Channel_a ... chemes#DFS


B) How should the GUI react to automatically changed channels?

I set my TL-WDR3600 to channel 56 and it was changed automatically twice (first to 140 (DFS) then to 40). But the GUI still says 56. That might confuse someone :)

Code: Select all

Wed Mar 23 23:36:41 2016 daemon.notice netifd: radio1 (20448): wlan1: DFS-CAC-COMPLETED success=1 freq=5280 ht_enabled=1 chan_offset=0 chan_width=1 cf1=5280 cf2=0

Wed Mar 23 23:53:09 2016 daemon.info hostapd: wlan1: IEEE 802.11 driver had channel switch: freq=5700, ht=1, offset=0, width=1 (20 MHz), cf1=5700, cf2=0

Thu Mar 24 04:39:04 2016 daemon.info hostapd: wlan1: IEEE 802.11 driver had channel switch: freq=5200, ht=1, offset=0, width=1 (20 MHz), cf1=5200, cf2=0
running 1.9.X (Built 20160321-2244 git@a36337c)

I know some users will find this a bit too technical but when they wonder why the channel they set have changed it's nice they can be helped.

Regards.

Re: 5 GHz DFS channels

Posted: Thu Mar 24, 2016 5:56 pm
by Lantis
This is a great suggestion and I looked into it. Unfortunately there is no easy way of finding out if the channel has changed. The config file doesn't get updated, and therefore most of the wireless tools don't report the correct channel number.

As you've noted the system log does capture it. However the log is of finite rolling length so we would then have to write a daemon looking for that line (which sucks).

If you can show me a reasonably simple way of detecting the channel changes, using iwinfo or iw, I'll implement it. Because I do think it is a great suggestion.

Re: 5 GHz DFS channels

Posted: Thu Mar 24, 2016 6:37 pm
by n8b
The GUI still reports channel 56 but plain iwinfo reports 40 :)

Code: Select all

root@Gargoyle:~# iwinfo
wlan1     ESSID: "Gargoyle 5GHz"
          Access Point: (MAC hidden)
          Mode: Master  Channel: 40 (5.200 GHz)
          Tx-Power: 15 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -92 dBm
          Bit Rate: unknown
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11an
          Hardware: (also hidden) [Atheros AR9580]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy1
Or this one with an asterisk at channel 40:

Code: Select all

root@Gargoyle:~# iwinfo wlan1 freqlist
  5.180 GHz (Channel 36)
* 5.200 GHz (Channel 40)
  5.220 GHz (Channel 44)
  5.240 GHz (Channel 48)
  5.260 GHz (Channel 52)
  5.280 GHz (Channel 56)
  5.300 GHz (Channel 60)
  5.320 GHz (Channel 64)
  5.500 GHz (Channel 100)
  5.520 GHz (Channel 104)
  5.540 GHz (Channel 108)
  5.560 GHz (Channel 112)
  5.580 GHz (Channel 116)
  5.600 GHz (Channel 120)
  5.620 GHz (Channel 124)
  5.640 GHz (Channel 128)
  5.660 GHz (Channel 132)
  5.680 GHz (Channel 136)
  5.700 GHz (Channel 140)

Re: 5 GHz DFS channels

Posted: Thu Mar 24, 2016 6:48 pm
by Lantis
Well there you go. I swear that used to only report the config set channel. Not the one in use.

I'll work on it

Re: 5 GHz DFS channels

Posted: Thu Mar 24, 2016 7:14 pm
by n8b
Great :D

Maybe the chosen channel should remain in the dropdown as "56 (DFS)" and a new box right to the dropdown could show the actual channel "40" ?

In this way the user can still see how he configured it.