adding VLAN disables 5 GHz Wi-Fi on RT-AC87R

[APnet]

I have run into a problem when trying to enable a simple port-based VLAN.

Once the appropriate scripts and config files are put in place, the VLAN seems to be set up OK, but the 5 GHz radio is disabled and cannot be restarted using the GUI.

The Advanced Settings > Wireless web page does not appear properly (only the General tab appears) and the Apply button has no effect.

Attempting to enable the 5 GHz radio in other places, such as on the Guest Network page, has no effect when Apply is pressed.

Removing the script and config file again allows the radio to start after a reboot.

Anybody have any ideas why configuring a VLAN would shut down the 5 GHz radio?


Firmware Version: 378.54_2

nat-start script:

#!/bin/sh
#
# lan ports 1-3 assigned to vlan1
robocfg vlan 1 ports "2 3 5 7t"
# port 4 to vlan4
robocfg vlan 4 ports "1t 7t"
#
vconfig add eth0 4
#
ifconfig vlan4 192.168.30.1 netmask 255.255.255.0 up
#
iptables -I FORWARD -i vlan4 -m state --state NEW -j ACCEPT
iptables -I FORWARD -i vlan4 -o br0 -m state --state NEW -j DROP
iptables -I FORWARD -i br0 -o vlan4 -m state --state NEW -j DROP
iptables -I INPUT -i vlan4 -j ACCEPT

dnsmasq.conf.add file:

interface=vlan4
dhcp-range=vlan4,192.168.30.100,192.168.30.200,255.255.255.0,86400s
dhcp-option=vlan4,3,192.168.30.1
dhcp-option=vlan4,6,192.168.30.1,0.0.0.0

 

[Virdo]

I do not have configured any vlans and use my RT-AC87U as a normal Wifi-router. I am using Merlins Rom ( for now "RT-AC87U_378.55_alpha1").
If I run "ip a l" in a ssh-shell i get a response that there is already a vlan1 and vlan2. Maybe you overwrite the default vlans? Just a thought.

Another idea is that I read that the 5GHz-cpu is bound in a very special way to the LAN-ports. If you look at this diagram you may get what i mean:

Maybe you break with your additional vlans the way how the 5GHz-cpu is connected to the other components. Especially if you use a port-based vlan-setup.

I know that this is no real solution but I hope that there are some aspects where you can do a deeper search.

 

[APnet]

I am still struggling with this. I tried different VLAN IDs and tried stopping and starting the switch during the configuration, but no luck.

Does anyone have VLANs working on this router?

 

[darkvoid]

The problem is in reconfiguring vlan 1:

robocfg vlan 1 ports "2 3 5 7t"

This reflects in "robocfg show" as "2 3 5t 7t", so suddenly port 5 has become tagged.

Update your script to use:

robocfg vlan 1 ports "2 3 5u 7t"

"robocfg show" now displays "2 3 5 7t", which is correct.

With the above 5ghz wifi seems to be working on my RT-87u.