OpenWrt Forum Archive

Topic: Few channels in 5 Ghz band

The content of this topic has been archived on 4 Apr 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

Hi,

I'm trying to figure out why, with OpenWRT, I have few channels in 5 GHz band. Before posting here I searched in the forum and in internet, finding nothing of useful.

I'm using an Ubiquiti RouterStationPro with Ubiquiti XR2 and XR5 cards (but I have identical situation with Buffalo WZR-HP-AG300H).

I'm in Italy, and according the European rules these are the frequencies allowed in my country.

This is what dmesg says

[  150.160000] cfg80211: Calling CRDA for country: IT
[  150.170000] cfg80211: Regulatory domain changed to country: IT
[  150.170000] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[  150.180000] cfg80211:   (2402000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm)
[  150.190000] cfg80211:   (5170000 KHz - 5250000 KHz @ 40000 KHz), (N/A, 2000 mBm)
[  150.200000] cfg80211:   (5250000 KHz - 5330000 KHz @ 40000 KHz), (N/A, 2000 mBm)
[  150.200000] cfg80211:   (5490000 KHz - 5710000 KHz @ 40000 KHz), (N/A, 2700 mBm)

And this is what iwlist says

root@ApCasa:~# iwlist wlan1 channel
wlan1     16 channels in total; available frequencies :
          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 132 : 5.66 GHz
          Channel 136 : 5.68 GHz
          Channel 140 : 5.7 GHz

So, the first thing I notice is that I cannot use channels 120, 124 and 128. The second and most annoying thing is that Luci let me to chose only 36,40, 44 and 48 channels. Why?

So I compiled my personal and very unrestrictive regulatory file for the "world domain", in order to make a test. This is dmesg output

[   41.190000] cfg80211: Calling CRDA to update world regulatory domain
[   41.200000] cfg80211: World regulatory domain updated:
[   41.200000] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[   41.210000] cfg80211:   (2402000 KHz - 2494000 KHz @ 40000 KHz), (N/A, 3000 mBm)
[   41.220000] cfg80211:   (5170000 KHz - 5250000 KHz @ 40000 KHz), (N/A, 3000 mBm)
[   41.230000] cfg80211:   (5250000 KHz - 5330000 KHz @ 40000 KHz), (N/A, 3000 mBm)
[   41.230000] cfg80211:   (5490000 KHz - 5600000 KHz @ 40000 KHz), (N/A, 3000 mBm)
[   41.240000] cfg80211:   (5650000 KHz - 5710000 KHz @ 40000 KHz), (N/A, 3000 mBm)
[   41.250000] cfg80211:   (5735000 KHz - 5835000 KHz @ 40000 KHz), (N/A, 3000 mBm)

and this the iwlist one

root@ApCasa:~# iwlist wlan1 channel
wlan1     21 channels in total; available frequencies :
          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 132 : 5.66 GHz
          Channel 136 : 5.68 GHz
          Channel 140 : 5.7 GHz
          Channel 149 : 5.745 GHz
          Channel 153 : 5.765 GHz
          Channel 157 : 5.785 GHz
          Channel 161 : 5.805 GHz
          Channel 165 : 5.825 GHz

I would have expected also channels 32, 42 and 46. Also in this case Luci permit me to select only few channels, and in particular 36, 40, 44, 48, 149, 153, 157, 161 and 165.

Is it a bug of Luci or what? What about missing channels?

Thanks in advance
FunMan

Is only a my problem? is it "normal"? Do I open a ticket?

Thanks
FunMan

Check the output of "iw list" - most channels are probably restricted.

jow wrote:

Check the output of "iw list" - most channels are probably restricted.

root@OpenWrt:~# iw list
Wiphy phy0
        Band 1:
                Capabilities: 0x11ce
                        HT20/HT40
                        SM Power Save disabled
                        RX HT40 SGI
                        TX STBC
                        RX STBC 1-stream
                        Max AMSDU length: 3839 bytes
                        DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 8 usec (0x06)
                HT TX/RX MCS rate indexes supported: 0-15
                Frequencies:
                        * 5180 MHz [36] (30.0 dBm)
                        * 5200 MHz [40] (30.0 dBm)
                        * 5220 MHz [44] (30.0 dBm)
                        * 5240 MHz [48] (30.0 dBm)
                        * 5260 MHz [52] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5280 MHz [56] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5300 MHz [60] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5320 MHz [64] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5500 MHz [100] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5520 MHz [104] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5540 MHz [108] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5560 MHz [112] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5580 MHz [116] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5600 MHz [120] (disabled)
                        * 5620 MHz [124] (disabled)
                        * 5640 MHz [128] (disabled)
                        * 5660 MHz [132] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5680 MHz [136] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5700 MHz [140] (30.0 dBm) (passive scanning, no IBSS, radar detection)
                        * 5745 MHz [149] (30.0 dBm)
                        * 5765 MHz [153] (30.0 dBm)
                        * 5785 MHz [157] (30.0 dBm)
                        * 5805 MHz [161] (30.0 dBm)
                        * 5825 MHz [165] (30.0 dBm)
                Bitrates (non-HT):
                        * 6.0 Mbps
                        * 9.0 Mbps
                        * 12.0 Mbps
                        * 18.0 Mbps
                        * 24.0 Mbps
                        * 36.0 Mbps
                        * 48.0 Mbps
                        * 54.0 Mbps
        max # scan SSIDs: 4
        max scan IEs length: 2261 bytes
        Coverage class: 16 (up to 7200m)
        Supported Ciphers:
                * WEP40 (00-0f-ac:1)
                * WEP104 (00-0f-ac:5)
                * TKIP (00-0f-ac:2)
                * CCMP (00-0f-ac:4)
                * CMAC (00-0f-ac:6)
        Available Antennas: TX 0x3 RX 0x3
        Configured Antennas: TX 0x3 RX 0x3
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * WDS
                 * monitor
                 * mesh point
                 * P2P-client
                 * P2P-GO
        software interface modes (can always be added):
                 * AP/VLAN
                 * monitor
        valid interface combinations:
                 * #{ managed, WDS, P2P-client } <= 2048, #{ AP, mesh point, P2P-GO } <= 8, #{ IBSS } <= 1,
                   total <= 2048, #channels <= 1, STA/AP BI must match
        Supported commands:
                 * new_interface
                 * set_interface
                 * new_key
                 * start_ap
                 * new_station
                 * new_mpath
                 * set_mesh_config
                 * set_bss
                 * authenticate
                 * associate
                 * deauthenticate
                 * disassociate
                 * join_ibss
                 * join_mesh
                 * remain_on_channel
                 * set_tx_bitrate_mask
                 * frame
                 * frame_wait_cancel
                 * set_wiphy_netns
                 * set_channel
                 * set_wds_peer
                 * tdls_mgmt
                 * tdls_oper
                 * probe_client
                 * set_noack_map
                 * register_beacons
                 * Unknown command (89)
                 * Unknown command (92)
                 * connect
                 * disconnect
        Supported TX frame types:
                 * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * mesh point: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
                 * (null): 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
        Supported RX frame types:
                 * IBSS: 0x40 0xb0 0xc0 0xd0
                 * managed: 0x40 0xd0
                 * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * mesh point: 0xb0 0xc0 0xd0
                 * P2P-client: 0x40 0xd0
                 * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
                 * (null): 0x40 0xd0
        Device supports RSN-IBSS.
        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Device supports TX status socket option.
        Device supports HT-IBSS.

Only 120-128 are restricted, others channels can be used with some limitations...

FunMan

yes, you are allowed to use the other channels if you have implemented this additional features.
I'm not sure about all of them, but a working radar detection is mandatory and it isn't implemented in ath9k (now).
so you are not allowed to use this channels.
There is some work done on that, but don't get your hopes up it will be available any time soon.

@FunMan

If you are compiling your own build  - take a look at package/mac80211/files/regdb.txt

R.

eleon216 wrote:

yes, you are allowed to use the other channels if you have implemented this additional features.
I'm not sure about all of them, but a working radar detection is mandatory and it isn't implemented in ath9k (now).
so you are not allowed to use this channels.
There is some work done on that, but don't get your hopes up it will be available any time soon.

Ok,
it begin to be clear now (at least for me smile )

So until the radar detection in ath9k is not implemented we cannot use these channels.... it's not a nice thing, and I hope that it will be implemented as soon as possible...

As I know it's a linux kernel implementation, not an OpenWrt one, right?

Thanks
FunMan

rolf2 wrote:

@FunMan

If you are compiling your own build  - take a look at package/mac80211/files/regdb.txt

R.

I already did it, this is "my" world regulatory domain

country 00:
    (2402 - 2494 @ 40), (N/A, 30)
    (5170 - 5250 @ 40), (N/A, 30)
    (5250 - 5330 @ 40), (N/A, 30)
    (5490 - 5600 @ 40), (N/A, 30)
    (5650 - 5710 @ 40), (N/A, 30)
    (5735 - 5835 @ 40), (N/A, 30)

Tried also with a less restrictive one, with no luck.

Thanks
FunMan

written_direcon wrote:

You can try the reghack from: http://luci.subsignal.org/~jow/reghack/

I'll try... but is not the same as modifying the regdb file?

Thanks
FunMan

No channel with any limitation can be used. Passive scanning flags prevent ap mode operation for example.

jow wrote:

No channel with any limitation can be used. Passive scanning flags prevent ap mode operation for example.

so, this patching utility doesn't help in the 5GHz range?

It does now.

jow:

It works perfectly on 1043ND and Attitude Adjustment final (untouched), thank you!

Frequencies:
                        * 2412 MHz [1] (30.0 dBm)
                        * 2417 MHz [2] (30.0 dBm)
                        * 2422 MHz [3] (30.0 dBm)
                        * 2427 MHz [4] (30.0 dBm)
                        * 2432 MHz [5] (30.0 dBm)
                        * 2437 MHz [6] (30.0 dBm)
                        * 2442 MHz [7] (30.0 dBm)
                        * 2447 MHz [8] (30.0 dBm)
                        * 2452 MHz [9] (30.0 dBm)
                        * 2457 MHz [10] (30.0 dBm)
                        * 2462 MHz [11] (30.0 dBm)
                        * 2467 MHz [12] (30.0 dBm)
                        * 2472 MHz [13] (30.0 dBm)
                        * 2484 MHz [14] (disabled)

If I understand it correctly, this is not model specific but Ath9k specific hack, so it will work on wdr3600 and maybe other routers that are using the same driver?

Dchard

correct

We could but ath9k employs additional limits on top of that.

The discussion might have continued from here.