--- title: AP+STA Single-Channel Concurrency slug: one/testing/network/wifi/ap-sta-scc docTags: createdAt: 2026-06-23T01:15:11.168Z --- Tests for Wi-Fi as Access Point + Station Single-Channel Concurrency (AP+STA SCC): running hotspot (AP) and client (STA) modes simultaneously on the **same band and channel**. ## Test sequence Repeat on each band (2.4 GHz, 5 GHz, 6 GHz): ::::WorkflowBlock :::WorkflowBlockItem Bring up an access point and connect to an external access point as a client, both on the same channel. ::: :::WorkflowBlockItem Confirm both interfaces stay associated simultaneously. ::: :::WorkflowBlockItem Measure throughput on each interface with `iperf3`. ::: :::: ## ✅ Test log: AP+STA same-channel (SCC) ::::BlockQuote Tested and recorded using build `1350` at 23 Jun 2026. :::Paragraph{listStyleType="disc" indent="1"} 5 GHz AP ::: :::Paragraph{listStyleType="disc" indent="1"} 5 GHz STA ::: :::: Environment: Debian Trixie; made sure that `NetworkManager`, `iw` and `dnsmasq` are present in the system. ::::WorkflowBlock :::WorkflowBlockItem Set Regulatory Domain if not set: ```bash sudo iw reg set HK ``` ::: :::WorkflowBlockItem Run to **see your Wi-Fi card name** ```bash nmcli device status | grep wifi ``` in our case it is called `wlxb06b11673af2`: ```console DEVICE TYPE STATE CONNECTION lo loopback connected (externally) lo wlxb06b11673af2 wifi disconnected -- ``` ::: :::WorkflowBlockItem The AP will live on a second virtual interface named `ap0` on the same phy, because one netdev can't be STA and AP simultaneously. `udev` will try to rename a freshly created `ap0` to a wlx\* predictable name, which breaks the NM profile binding. Pin the name with a `.link` file: ```bash sudo tee /etc/systemd/network/10-ap0.link >/dev/null <<'EOF' [Match] OriginalName=ap0 [Link] Name=ap0 EOF ``` Apply it: ```bash sudo udevadm control --reload ``` ::: :::WorkflowBlockItem Create a LAN bridge (NAT + DHCP) Change `192.168.50.1/24` if it overlaps the upstream AP subnet. These two subnets must differ; otherwise, routing collapses. ```bash sudo nmcli connection add type bridge con-name br-lan ifname br-lan \ ipv4.method shared ipv4.addresses 192.168.50.1/24 \ ipv6.method ignore \ connection.autoconnect yes ``` Bring it up: ```bash sudo nmcli connection up br-lan ``` ::: :::WorkflowBlockItem Verify that the bridge is NM-owned (not "externally" managed): ```bash nmcli -f GENERAL.STATE device show br-lan # must NOT say 'externally' ip addr show br-lan | grep inet # expect 192.168.50.1/24 pgrep -a dnsmasq # expect one bound to br-lan ``` In our case: ```console $ nmcli -f GENERAL.STATE device show br-lan GENERAL.STATE: 100 (connected) $ ip addr show br-lan | grep inet inet 192.168.50.1/24 brd 192.168.50.255 scope global noprefixroute br-lan $ pgrep -a dnsmasq 11182 /usr/sbin/dnsmasq --conf-file=/dev/null --no-hosts --keep-in-foreground --bind-interfaces --except-interface=lo --clear-on-reload --strict-order --listen-address=192.168.50.1 --dhcp-range=192.168.50.10,192.168.50.254,3600 --dhcp-leasefile=/var/lib/NetworkManager/dnsmasq-br-lan.leases --pid-file=/run/nm-dnsmasq-br-lan.pid --conf-dir=/etc/NetworkManager/dnsmasq-shared.d ``` ::: :::WorkflowBlockItem Create an STA uplink Replace **wlan0**, **YourHomeWiFi**, and **upstream-password** with your values: ```bash sudo nmcli connection add type wifi con-name sta-uplink ifname wlan0 \ ssid YourHomeWiFi \ wifi-sec.key-mgmt wpa-psk wifi-sec.psk 'upstream-password' \ ipv4.method auto ipv6.method ignore \ connection.autoconnect yes ``` Bring it up: ```bash sudo nmcli connection up sta-uplink ``` Verify (change **wlan0** here first): ```bash iw dev wlan0 info ``` We got this output: ```console iw dev "wlxb06b11673af2" info Interface wlxb06b11673af2 ifindex 5 wdev 0x1 addr b0:6b:11:67:3a:f2 type managed wiphy 0 channel 36 (5180 MHz), width: 80 MHz, center1: 5210 MHz txpower 3.00 dBm multicast TXQ: qsz-byt qsz-pkt flows drops marks overlmt hashcol tx-bytes tx-packets 0 0 0 0 0 0 0 0 0 ``` ::: :::WorkflowBlockItem Create an AP profile ```bash sudo nmcli connection add type wifi con-name ap-downlink ifname ap0 \ ssid FlipperOne \ wifi-sec.key-mgmt wpa-psk wifi-sec.psk 'flipperone' \ 802-11-wireless.mode ap \ 802-11-wireless.powersave 2 \ master br-lan slave-type bridge \ connection.autoconnect no ``` ::: :::WorkflowBlockItem Bring-up helper. This is the piece that makes SCC work: - it brings the STA up first (so it owns the channel context), - reads the STA's channel/width, - creates `ap0` with a stable MAC set atomically at creation, - pins the AP chandef to the STA, - and activates the AP. First, write an `~/apsta-up` script: ```bash sudo tee ~/apsta-up >/dev/null <<'EOF' #!/bin/sh # Bring up an SCC AP on ap0 locked to the STA's current channel. set -eu STA_CON=sta-uplink AP_CON=ap-downlink AP_IF=ap0 # 1. resolve the base wifi device (first real wifi; never p2p-dev, never ap0) STA=$(nmcli -t -f DEVICE,TYPE device status \ | awk -F: -v ap="$AP_IF" '$2=="wifi" && $1!=ap {print $1; exit}') [ -n "$STA" ] || { echo "apsta: no wifi device found" >&2; exit 1; } # 2. ensure uplink is up; wait for association (channel-context owner) nmcli connection up "$STA_CON" >/dev/null 2>&1 || true i=0 while :; do CH=$(iw dev "$STA" info 2>/dev/null | awk '/channel/{print $2}') [ -n "${CH:-}" ] && break i=$((i+1)); [ "$i" -ge 30 ] && { echo "apsta: STA not associated after 30s" >&2; exit 1; } sleep 1 done WMHZ=$(iw dev "$STA" info | sed -n 's/.*width: \([0-9]*\).*/\1/p') [ "$CH" -le 14 ] && BAND=bg || BAND=a # 3. stable locally-administered MAC for the AP vif (distinct from STA on same phy) PHY=$(iw dev "$STA" info | awk '/wiphy/{print "phy"$2}') MAC=$(cat /sys/class/net/"$STA"/address) APMAC="02:${MAC#*:}" # 4. (re)create ap0 with the MAC set atomically at creation iw dev "$AP_IF" del 2>/dev/null || true iw phy "$PHY" interface add "$AP_IF" type __ap addr "$APMAC" # 5. pin AP chandef to the STA (SCC) and force the stable MAC (disables randomization) nmcli connection modify "$AP_CON" \ 802-11-wireless.band "$BAND" \ 802-11-wireless.channel "$CH" \ 802-11-wireless.cloned-mac-address "$APMAC" # channel-width only exists on NM >= 1.50; ignore failure on older releases nmcli connection modify "$AP_CON" 802-11-wireless.channel-width "${WMHZ:-20}" 2>/dev/null || true # 6. activate nmcli connection up "$AP_CON" echo "apsta: $AP_IF up band=$BAND ch=$CH width=${WMHZ:-20} mac=$APMAC (matched to $STA)" EOF ``` Set script permissions: ```bash sudo chmod +x ~/apsta-up ``` Run the script: ```bash sudo ~/apsta-up ``` Example output: ```console $ sudo ./apsta-up Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/9) apsta: ap0 up band=a ch=36 width=80 mac=xx:xx:xx:xx:xx:xx (matched to wlxb06b11673af2) ``` ::: :::WorkflowBlockItem Check network connectivity: ```bash ping flipper.net ``` ::: :::WorkflowBlockItem Connect to your freshly created SSID `FlipperOne` with your phone/laptop and check the network connectivity. ::: ::::