Could not add STA to kernel driver

[Markus Theil]

Hi,

On 8/5/20 11:08 AM, Marek.Floriańczyk wrote:
> Hi
>
> I have a question.  I have Debian Buster with hostapd 2.7 from packages. I 
> would like to run AP with 80 devices connected to it without any encryption, 
> at the bottom there is my configuration file.
I don't know why this happens after 10 STAs for you, but iwlwifi/mvm
supports
at most 16 STAs, as far as I can see. So you better look after a card
which can
actually handle 80 devices.

Please note that having a NIC which can connect 80 devices and having a
nicely working
setup with 80 devices transmitting concurrently are two different things.
If a large amount of your devices are transmitting concurrently, I'd
advise you to use multiple
APs tuned to different channels, each handling a much lower amount of
clients. Maybe 20 - 30.
If your setup works after using multiple APs also depends on the
external interference in the environment.

Furthermore I would advise you to use 5 GHz channels if possible (I know
Intel NICs don't support 5 GHz in AP
mode).

Markus
> The problem is that after 11 devices has been connected, I can see in hostapd 
> logs this message:
> wlp3s0: STA 4c:11:ae:f9:a0:fc IEEE 802.11: authenticated
> wlp3s0: STA 4c:11:ae:f9:a0:fc IEEE 802.11: associated (aid 11)
> wlp3s0: AP-STA-CONNECTED 4c:11:ae:f9:a0:fc
> wlp3s0: STA 4c:11:ae:f9:a0:fc RADIUS: starting accounting session 
> 7D19D5A198595E57
> wlp3s0: STA 4c:11:ae:f9:7c:e4 IEEE 802.11: Could not add STA to kernel driver
> wlp3s0: STA 4c:11:ae:f8:ee:fc IEEE 802.11: Could not add STA to kernel driver
>
> I have kernel
> vmlinuz-4.19.0-10-amd64
>
> Debug from dmesg about wifi module:
> [    7.276894] Intel(R) Wireless WiFi driver for Linux 
> [    7.317193] iwlwifi 0000:03:00.0: firmware: direct-loading firmware 
> iwlwifi-3168-29.ucode 
> [    7.318027] iwlwifi 0000:03:00.0: loaded firmware version 29.1044073957.0 
> op_mode iwlmvm 
> [    7.516613] iwlwifi 0000:03:00.0: Detected Intel(R) Dual Band Wireless AC 
> 3168, REV=0x220 
> [    7.548539] iwlwifi 0000:03:00.0: base HW address: d4:3b:04:51:69:e0 
> [    7.670030] iwlwifi 0000:03:00.0 wlp3s0: renamed from wlan0
>
> My computer is Udoo x86 with this wifi module:
> https://shop.udoo.org/kit-m2-wifi-bt.html
>
> hostapd.conf
> # 
> # nl80211 mode 
> # 
>
> ssid=fmcode 
> interface=wlp3s0 
> hw_mode=g 
> channel=5 
> #bridge=br0 
> driver=nl80211 
>
> logger_syslog=1 
> logger_syslog_level=1 
> wmm_enabled=0 
> wpa=0 
> preamble=0 
>
> #wpa_psk=
> #wpa_passphrase=
> #wpa_key_mgmt=WPA-PSK 
>
> #wpa_pairwise=TKIP 
> #rsn_pairwise=CCMP 
> #auth_algs=1 
> #macaddr_acl=0 
>
> #noscan=1 
>
> ### IEEE 802.11n 
> #ieee80211n=1 
> #ht_capab= 
> #country_code=US 
> #ieee80211d=1 
> ### IEEE 802.11n 
>
> ### IEEE 802.11a 
> #hw_mode=a 
> ### IEEE 802.11a 
>
> ### IEEE 802.11ac 
> #ieee80211ac=1 
> #vht_capab=[MAX-MPDU-11454][SHORT-GI-80][TX-STBC-2BY1][RX-STBC-1][MAX-A-MPDU-
> LEN-EXP3] 
> #vht_oper_chwidth=1 
> #vht_oper_centr_freq_seg0_idx=42 
> ### IEEE 802.11ac 
>
> # controlling enabled 
> ctrl_interface=/var/run/hostapd 
> ctrl_interface_group=0
>
> #End
>
> Any idea why only 10 devices can be connected. Actually I have the same issue 
> on my laptop with different hardware.
>
> Best Regards
> Marek
>
>
>
>
>
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-- 
Markus Theil

Technische Universität Ilmenau, Fachgebiet Telematik/Rechnernetze
Postfach 100565
98684 Ilmenau, Germany

Phone: +49 3677 69-4582
Email: markus[dot]theil[at]tu-ilmenau[dot]de
Web: http://www.tu-ilmenau.de/telematik