Max connected users limit Wifi AP Raspberry Pi 3b+

[ezimmert]

For an educational project, I ran several tests to check what are the Rpi3b+ capabilities as a Wifi AP in a classroom (using integrated Wifi chip).

The Wifi hotspot is created with Hostapd and dnsmasq. The connected users can then access to a local workspace (nginx server in reverse proxy for node.js and fastcgi for php).

I tried both following config for Hostapd:

1.

Code: Select all

interface=wlan0
driver=nl80211
ssid=xxxxxx
hw_mode=g
channel=7
wmm_enabled=1
ht_capab=[HT40][SHORT-GI-20][DSSS_CCK-40]
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=xxxxxxxx
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP
rsn_pairwise=CCMP

2.

Code: Select all

interface=wlan0
driver=nl80211
ssid=xxxxxx
hw_mode=a
channel=36
ieee80211n=1
ieee80211ac=1
ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40]
wmm_enabled=1
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=xxxxxxxx
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP
rsn_pairwise=CCMP

In both cases, I was able to connect 14 iPads to the AP.

Each time I tried to connected another device, it said wrong password.
If a device was disconnected, it became availalbe for another one to connect with always the same limit of 14.

The Raspberry Pi was fine with less than 10% CPU usage and more than 60% of RAM available.

Is there a parameter to unlock this limit?
Is this a driver limit? an Hostapd limit? a hardware limit?

Also, one of the test was to play a 720p video simultaneously on all devices and during the tests, a few devices were disconnected from the hotspot.

I can't figure out the origin of the problem.
Thanks for your help.

[mikerr]

May be a driver limit, see this old thread for limits of various wifi adaptors:

viewtopic.php?p=726779

[ezimmert]

That's possible indeed. Although, reading this thread, it seems to have no limits of this kind: https://raspberrypi.stackexchange.com/q ... -3-hotspot.

[mina]

See also this: https://www.raspberrypi.org/forums/view ... x#p1472522 and this https://github.com/raspberrypi/linux/issues/3010.