Configuring AX200 as Access Point (AP)mode in OpenWrt

kalma · February 20, 2025, 7:45pm

Hello Everyone,

This for those who trying to use ax200 WiFi in AP mode for OpenWrt.
I have AX200NGW installed in Raspberry PI CM4 Ultra Board, I have installed the required firmware’s for the ax200 card on OpenWrt, here is what installed:

At beginning, ax200 won’t work in AP mode, but after some searching and checking this forum I finally got it to work in 2.4GHz only.

For me, the case was disabling Wireless network on device named radio0.network2.

My understanding for this I think is that the WiFi card cannot operate in both AP and client mode at the same time, so disabling client mode (Wireless Network) on device (radio0.network2) and only enable on device (phy0-ap0) works for me.

Now, AX200 works in AP mode in 2.4GHz frequency but not in 5GHz or 6GHz.

and my wireless configuration is:

root@OpenWrt:~# cat /etc/config/wireless

config wifi-device 'radio0'
        option type 'mac80211'
        option path 'scb/fd500000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:05.0/0000:05:00.0'
        option channel '13'
        option band '2g'
        option htmode 'HE80'
        option cell_density '1'
        option country 'US'
        option txpower '22'
        option hw_mode 'ap'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'sae-mixed'
        option key 'wifipassword'

config wifi-iface 'wifinet1'
        option device 'radio0'
        option mode 'ap'
        option ssid 'OpenWrt'
        option encryption 'none'
        option disabled '1'

For 5GHz, from the output of command iw phy, check where states available frequency bands, specific the section where sates EHT Iftypes: AP

The channels allowed in 5GHz are: 36, 40, 44, 48, 149,153, 157, 161, 165

EHT Iftypes: AP
                        EHT MAC Capabilities (0x0000):
                        EHT PHY Capabilities: (0x0000000000000000):
                        EHT MCS/NSS: (0x):
                        EHT bw <= 80 MHz, max NSS for MCS 8-9: Rx=0, Tx=0
                        EHT bw <= 80 MHz, max NSS for MCS 10-11: Rx=0, Tx=0
                        EHT bw <= 80 MHz, max NSS for MCS 12-13: Rx=0, Tx=0
                Frequencies:
                        * 5180 MHz [36] (22.0 dBm)
                        * 5200 MHz [40] (22.0 dBm)
                        * 5220 MHz [44] (22.0 dBm)
                        * 5240 MHz [48] (22.0 dBm)
                        * 5260 MHz [52] (22.0 dBm) (no IR, radar detection)
                        * 5280 MHz [56] (22.0 dBm) (no IR, radar detection)
                        * 5300 MHz [60] (22.0 dBm) (no IR, radar detection)
                        * 5320 MHz [64] (22.0 dBm) (no IR, radar detection)
                        * 5340 MHz [68] (disabled)
                        * 5360 MHz [72] (disabled)
                        * 5380 MHz [76] (disabled)
                        * 5400 MHz [80] (disabled)
                        * 5420 MHz [84] (disabled)
                        * 5440 MHz [88] (disabled)
                        * 5460 MHz [92] (disabled)
                        * 5480 MHz [96] (disabled)
                        * 5500 MHz [100] (22.0 dBm) (no IR, radar detection)
                        * 5520 MHz [104] (22.0 dBm) (no IR, radar detection)
                        * 5540 MHz [108] (22.0 dBm) (no IR, radar detection)
                        * 5560 MHz [112] (22.0 dBm) (no IR, radar detection)
                        * 5580 MHz [116] (22.0 dBm) (no IR, radar detection)
                        * 5600 MHz [120] (22.0 dBm) (no IR, radar detection)
                        * 5620 MHz [124] (22.0 dBm) (no IR, radar detection)
                        * 5640 MHz [128] (22.0 dBm) (no IR, radar detection)
                        * 5660 MHz [132] (22.0 dBm) (no IR, radar detection)
                        * 5680 MHz [136] (22.0 dBm) (no IR, radar detection)
                        * 5700 MHz [140] (22.0 dBm) (no IR, radar detection)
                        * 5720 MHz [144] (22.0 dBm) (no IR, radar detection)
                        * 5745 MHz [149] (22.0 dBm)
                        * 5765 MHz [153] (22.0 dBm)
                        * 5785 MHz [157] (22.0 dBm)
                        * 5805 MHz [161] (22.0 dBm)
                        * 5825 MHz [165] (22.0 dBm)
                        * 5845 MHz [169] (disabled)
                        * 5865 MHz [173] (disabled)
                        * 5885 MHz [177] (disabled)
                        * 5905 MHz [181] (disabled)

But in Device Configuration --> Operating frequency configuration these channels are not available to choose from, that’s why 5GHz is not working.

If there is firmware or driver will allow these channels to be chosen, I think the card will operate in 5GHz.
Finally, It's working in 2.4 GHz but signal coverage is poor, I guess I will continue to tweak the configuration to try and fix this.
Thank you, and if anyone have advice or suggestion to improve this will be appreciated.

patrakov · February 20, 2025, 11:21pm

This device actually can operate as one AP and one client. Two AP SSIDs are not possible.

As for the 5 GHz AP operation, it is also possible, with a twist: there must exist a client connection to a different pre-existing AP on the same card, so a repeater scenario is possible and I have done that for testing. The reason is that Intel cards lack the circuitry required for detecting radars. They rely on the AP they connect to for this task and thus cannot operate standalone.

kalma · February 24, 2025, 12:06pm

Thank you @patrakov,
Yes indeed, it’s working as a repeater scenario, however if the main AP went off, it doesn’t automatically fallback to standalone AP mode, you have to login and disable client connection.

Did you test the coverage in lab? Because for me it’s very poor and doesn’t go far beyond room space (4 to 5 meters), I want to know if this is a card specific limitation or OpenWrt?

patrakov · February 24, 2025, 12:44pm

The fact that it does not fall back to a standalone AP mode on 5 GHz
is not a bug, it is a limitation of the card. On 2.4 GHz, if it
happens, it is a bug.

I haven't really tested the coverage in the lab, because for me, it is
unconditionally a wrong metric. "Coverage with X Mbps of guaranteed
throughput" with pre-agreed X (I use X=400 Mbps) is what should be
used instead.

In any case, I am traveling now and can't check things, but I do
remember testing across the wall. The results were indeed not so good
in terms of throughput, but it did not sound like an OpenWrt
limitation.

kalma · February 24, 2025, 1:42pm

It doesn’t actually fallback to AP mode in 2.4 GHz, so i guess it’s a bug like you said.
But for coverage, I didn’t get to throughput aspects yet, I’m still testing the signal across walls, and it’s very bad, you can barley get signal 4~5 m far from the router, but I guess it’s card limitation.
I will try to get other wifi card to test with and see the result.

patrakov · February 24, 2025, 2:38pm

In my experience, the quality of the pigtail cables also matters. Older ones from 2013 attenuate 5 GHz too much.

kalma · February 24, 2025, 3:23pm

Much appreciate, I will be checking that also.
But the same for 2.4GHz the distance coverage doesn’t exceed 5 m, weird