@MrBeatnik 

 

You have very interesting case. You are correct, there is no setting to "persist" ethernet backhaul connection in one direction, or otherwise turn the WiFi backhaul connection option off.

Because of that, if both these Deco, M5 and Office, can establish WiFI backhaul link to the rest of the Deco mesh, either could do that and second one will switch to Ethernet.

 

I can tell you how backhauls work and that may help to figure how to reduce chance for Ethernet backhaul to swap direction. There is no fix, just workarounds.

 

First of all, when you do Deco mesh restart at 5am, you are tossing the coin. Which one of M5 and Office Deco comes online first - will connect to the rest of Deco mesh by WiFi. When second of these two comes online it'll find working Ethernet backhaul and switch to it.

If you stop rebooting your Deco mesh, that will reduce chances of Ethernet backhaul going the wrong way after reboot.

When Deco node establishes Ethernet backhaul, it does not switch to WiFi unless there is a reason. That reason would be unplugging of Ethernet cable or Deco on the other side of Ethernet cable (M5 in your case) losing connection to Deco mesh, even briefly.

 

When Deco node establishes WiFi backhaul to another Deco, it stays connected to that Deco unless it loses WiFi signal to it. Then, it will briefly go offline while searching for other Deco with stronger signal to connect to. By default, Satellite Deco prefers connecting over WiFi to Main Deco, even if signal between them is very weak.

 

Suppose, you have Ethernet backhaul the way you want: Office to M5, then the only reason for Office to switch to WiFi would be for M5 to lose its WiFi link to Deco mesh (even briefly) or go offilne (also even briefly). 

There is of course flaky Ethernet cable reason, too, but it is less likely - still check cable and that its both ends are tightly plugged into Office and M5 Decos Ethernet ports.

 

 

These are the reasons for M5 to lose its link to Deco mesh I can think of:

 

1. Brief loss of power to M5;

 

2. Brief loss of power to Deco that M5 connects to by WiFi. In your "good" diagram M5 connects to Dining Room Deco. If Dining Room Deco briefly lost power or rebooted, M5 will go offline for a moment and Office Deco will switch to WiFi backhaul.

 

3. M5 has weak WiFi backhaul signal, loses it and switches to Deco with stronger WiFi backhaul signal. It may be possible that after Deco mesh reboot M5 connected to Main Deco (Living Room) instead of Dining Room Deco. If WiFi backhaul to Main Deco is weak, at some random moment M5 will briefly disconnect to switch to Dining Room, and that is when Office will switch to WiFi backhaul.

 

 

So, what to do about that all:

 

1. Disable regular Deco mesh reboot. If you want to keep Deco mesh reboot, connect Office Deco through Smart plug such as TP-Link Kasa HS103, program that smart plug to power off and on Office Deco 5 minutes after Deco mesh reboot;

 

2. Use Connection Preference feature to force M5 always connect to Dining Room, see Part 1 of the following TP-Link document: How to select a preferred signal source on the Deco App

 

3. Connect M5 Deco through UPS (uninterruptible power supply) to ensure it is not impacted by brief power fluctuations.

 

4. Move Office Deco and Dining Room Deco further away from each other, so that Office Deco can't establish WiFi link to Dining Room Deco.

  @Alexandre. Many thanks for taking the time to respond.

 

So, what to do about that all:

 

1. Disable regular Deco mesh reboot. If you want to keep Deco mesh reboot, connect Office Deco through Smart plug such as TP-Link Kasa HS103, program that smart plug to power off and on Office Deco 5 minutes after Deco mesh reboot;

 

2. Use Connection Preference feature to force M5 always connect to Dining Room, see Part 1 of the following TP-Link document: How to select a preferred signal source on the Deco App

 

3. Connect M5 Deco through UPS (uninterruptible power supply) to ensure it is not impacted by brief power fluctuations.

 

4. Move Office Deco and Dining Room Deco further away from each other, so that Office Deco can't establish WiFi link to Dining Room Deco.

 

#1 That's a great idea about the plug. I'm fairly confident that the problem happens well after a reboot, but I can set up a subsequent reboot to make sure. I like to keep the reboots as it has resolved other issues in the past when the system is up for a week.

 

#2 I forgot to mention I already do this.

 

#3 Might help others with the issue, but not viable for me with location/need.

 

#4 Yes I will try this as well.

 

 

As a #5, I think I could extend/add ethernet backhaul from M5 to Dining Room, even termporarily. If that resolves the issue it would point to M5 losing WiFi brielfy as the cause. In any case, that's a couple of options I can try. Thank you!