As Access Point (WiFi Repeater): How to set up multiple WiFi/SSID

Question

I had successfully set up my raspberry pi as an access point as WiFi repeater followed this guide: Access point as WiFi router/repeater, optional with a bridge.

I would like to set up my raspberry pi to broadcast multiple WiFi/SSIDs like how a router can have two or more WiFi to connect to.

I wonder if I could build this with on-chip built-in RPi4 or with additional WiFi dongle(s).

If it’s possible with an only built-in chip of RPi4, how to set it up?

If it’s need additional WiFi-dongle(s), how to set it up?

Thank you.

Answer 1

An access point is defined by its ssid. If you want to have more than one ssid then you have to create additional access points, one for each ssid. The built-in WiFi device of a Raspberry Pi can only spawn one access point. You can verify it with:

rpi ~$ iw phy0 info
--- snip ---
valid interface combinations:
         * #{ managed } <= 1, #{ P2P-device } <= 1, #{ P2P-client, P2P-GO } <= 1,
           total <= 3, #channels <= 2
         * #{ managed } <= 1, #{ AP } <= 1, #{ P2P-client } <= 1, #{ P2P-device } <= 1,
           total <= 4, #channels <= 1

Here you find in the second combination #{ AP } <= 1, that means: number of access points less or equal one. So you have to add an USB/WiFi dongle for each additional ssid. Because you used systemd-networkd following the setup Access point as WiFi router/repeater, optional with a bridge it is not a big issue to add an access point. Just plug in a compatible USB/WiFi dongle and you will find an interface wlan1. Using the example in the setup then configure it.

To setup wpa_supplicant for the additional access point using wlan1 create these files with your settings:

rpi ~$ sudo -Es
rpi ~# cat > /etc/wpa_supplicant/wpa_supplicant-wlan1.conf <<EOF
country=DE
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
    ssid="RPiNet2"
    mode=2
    frequency=2412
    key_mgmt=WPA-PSK
    proto=RSN WPA
    psk="verySecretPassword"
}
EOF

rpi ~# chmod 600 /etc/wpa_supplicant/wpa_supplicant-wlan1.conf
rpi ~# systemctl disable wpa_supplicant.service
rpi ~# systemctl enable [email protected]

rpi ~# cat > 16-wlan1.network <<EOF
[Match]
Name=wlan1
[Network]
Address=192.168.5.1/24
DHCPServer=yes
[DHCPServer]
DNS=84.200.69.80 1.1.1.1
EOF

rpi ~# systemctl start [email protected]
rpi ~# systemctl daemon-reload
rpi ~# systemctl restart systemd-networkd.service

Now you should find a second ssid RPiNet2 on the air.