AIMesh network Topology change every 20 seconds

[therac]

I have AC68U running 186.13 firmware, ethernet cable link to an AC67U running latest stock Asuswrt firmware (AC1900) connected as AImesh node. This in turn links over wifi to a further AC67U some distance away, also connected through the first AC67U as an AImesh node.
The system log on the main router generates the following message every 20 seconds :
Jul 17 22:34:25 kernel: br1: port 6(wds1.6.501) received tcn bpdu
Jul 17 22:34:25 kernel: br1: topology change detected, sending tcn bpdu

Can anyone explain what is likely to be the problem, and suggest a fix?
Also what does br1: port 6(wds1.6.501) actually mean in physical terms so that I can find out which bit of the network is playing up,
Appreciate any advice
Thanks

 

[mmacedo]

Do you have a Sonos speaker?

 

[therac]

No. A number of Amazon dots and firetv devices plus 3 or 4 intelligent plugs. All wifi connected. Plus two mains ethernet extenders, and a bridged repeater

 

[mmacedo]

I had issues in the past with Sonos and STP - spanning tree protocol, when connecting more than one speaker thru ETH. I had to leave all them connected to WiFi and that solved.

I'd suggest troubleshooting, disconnecting the extenders and repeaters and then reconnecting one at each time until you find the culprit.

 

[therac]

Thanks.
I tried to set up the second ac67u as a repeater, but hit the problem of repeated deauthentication every 20 mins or so, documented elsewhere in the forums as a suspected bug in Asus closed code. Switched Back to using it as an aimesh node, but although its been through factory reset several times the problem as noted above reappears. I know the wifi link is marginal as the two buildings have thick stone walls, but the problem really seems to have got worse since we had to habe a new utility smart meter connected. Could be interference?

Can you fit external aerials to an asus router?