I've been pretty happy with the DL-WRX36.
However, I've just noticed something very odd. Ethernet broadcast does not seem to work "sometimes".
Here's my set-up:
I have 3 DL-WRX36 functioning in dumb AP mode.
They are all bridged together for roaming but none of 802.11r, 802.11k or 802.11v are configured.
All 3 are configured on different 2.5 GHz and 5 GHz channels and have different 802.11ax colors.
I have a rather complex set up with VLANs and use new-style VLANs (bridging the untagged interface).
All three units have exactly the same configuration, they all get their address via DHCP, and the /etc/config/* files are all the same, except for hostnames and wifi channels and colors.
Now to the weird behavior:
I've noticed that while the station to AP traffic always works perfectly fine, station to station traffic sometimes didn't work. I narrowed it down to ARP traffic not flowing properly.
After investigation, I've found out that on stations connected to the 5 GHz band of one of the three units, Ethernet broadcasts were not being received. If Ethernet broadcasts are not working, then ARP doesn't work, and that explains why station-to-station traffic does not work.
To confirm the problem was Ethernet broadcast, if I add static ARP entries to the stations, then station-to-station traffic works fine.
I started investigating the problem with broadcasts. This is how I test:
The router behind the bridged/switched APs runs a ping to the wireless LAN broadcast address.
Tcpdump on all three APs see the broadcast ping arriving on the ethernet port.
Tcpdump on all three APs see the broadcast ping being emitted on both wireless LANs (2.5 GHz and 5 GHz) bridged to the ethernet port.
All the stations connected to two of the APs received the broadcast.
But on the last "problem" AP, the broadcast is only received on the stations connected to the 2.5 GHZ wireless network. Any station connected to the 5 GHz network never receives the broadcast ethernet frame.
I've also tried with multicast traffic. It does goes through.
I've tried changing channels on the problem AP, it does not help.
I'm starting to think that the problem AP may be a bad unit.