@CDH70  Your Deco nodes probably connected wirelessly because I believe they should be connected to a LAN port on the main unit (connected to router), either directly or (per my understanding), through the switch.  If you can access the configuration settings there may be an option to switch to Ethernet Backhaul that you need to toggle now that you seem to have connected it to a LAN through the switch.

  @jzchen Thanks for responding. There is no configuration setting to turn on/off backhaul, as the Deco units are supposed to automatically switch to it. I had my main Deco running directly from my modem, then feeding a switch and had my other 2 Deco units running off that switch. No dice. I have now tried connecting all 3 Deco units directly to my modem. No dice. All of my drops are 1 jack, so I don't really have a way to wire Deco 1>Deco 2>Deco 3 that I can tell.

TP-Link Support is horrific, off-shore trash, and is worthless. Not only do they just point me to the support pages I have already looked at, you never get the same person and they continuously ask for information that I have already provided. They can't tell me specifically what 16-port, rack mount switch of theirs I could try in order to get backhaul working, and searching for any switches that support ieee 1905.1 is fruitless. My main switch is a Netgear JGS524 which is feeding 9 of my 10 network drops.

  @CDH70 

Google this support article please and hopefully the steps work:

General Questions About the Ethernet Backhaul Feature on Deco Mesh Systems

  @CDH70 

You did not tell what occurs when you plug Deco 2 and/or Deco 3 to Deco 1, directly and via the Ethernet cables in the walls.

  @CDH70 This looks like a valid usage of Deco in AP mode.
The app should show the two satellites connected by wire (not by wifi) to the main Deco.  The app will always show only the main Deco as connected to the Internet.

  @yves_b I connected Deco 1 to Deco 2 via ethernet cable, with no change in connectivity. I am unable to daisy chain all 3, as I only have 1 jack at each network drop.

  @yves_b All Deco units are connected directly to my modem via Cat6.

  @CDH70 In Access Point mode, the "main" Deco router will relinquish DHCP duties to a router ahead of it, but connected to the "modem/ONT".  When you wire the other two Decos directly to the "modem" they will not Mesh with the main Deco, as they are supposed to be behind, meaning two wires go into the main Deco, one from WAN, and the LAN to the other two.  If you try to set up all three connected to the modem/gateway, then try to set up Deco Mesh, the only way they can do that is wirelessly.

I need to check on the specs of that Netgear switch...

Here's how I believe it should be wired: Fiber provides an ONT? Do you mind sharing which ISP? Did they provide you a router? ONTs are not routers unless you have service like AT&T which requires use of their gateway... ONT -> Deco (set up as router) -> Netgear switch (multiple connections) -> rest of house - (jack to) each of the other two.