@TP-Link Deco 
It take a long time to understand those essentials points on star network configuration:

- Upgrade to the last current firmware all the deco nodes
- it can't be ethernet backhaul if you have several switches in the architecture. The main deco has to give its output to one switch entry, and between this main deco and the other slaves, it can be only one switch.
- I had also a D-Link switch (DGS-1008A), I did not succeed to set-up ethernet backchaul. after replacing with tp-link one (LS1008G), rock'n roll !!

Good Luck

@TP-Link Deco 

Hello i have a strange problem with my Backhaul conection between 2 Deco M5 devices.

If i connect them like this:

Then my Modem/Router (SpeedPort Plus) is restarting every 4-5 minutes.

If I connect them directly anything works (slow 100Mbps but stable)

Any ideas what is wrong.

Thanks

@TP-Link Deco I found the problem,

i forgot the cable from modem to switch so i had a network loop.

I remove it an now everything is fine (about 680Mbps on booth Deco modules)

@TP-Link Deco 

Hello , have a quick question.

If i setup my Deco X20 (3 of them)  as:

In Access Point mode:

You can connect all the Deco units directly to your home modem/router/switch as you want. The system will work as expected. 

Will a "Mesh" still be able to be used, will connected devices move between access point as needed automatically? Or will a device need to specifiy which AP to use?

@TP-Link Deco 

I'd like to verify below for making a purchase decision: Considering buying Deco M9-Plus (3 units)

My duplex has very thick walls between the floors and wifi signals CAN'T propagate between ground floor and 1st floor. Walls between rooms of the same floor are OK for wifi.

My desired set-up is shown below:

* Deco1 (main deco) is connected by ethernet to the modem.

* Deco1 (main deco) provides ethernet backhaul to Deco2

* Deco2 is connected by ethernet backhaul to Deco1 (main deco)

* Deco2 provides wireless backhaul to Deco3, NOT Deco1 (main deco)

* Deco3 is connected by wireless backhaul to Deco2, NOT to Deco1 (main deco)

If Deco 3 tries to connect to main deco wirelessly, it will not work because of the thick floor walls blocking wifi signals.

Questions:

1- Is this topology possible?

2- Will all decos be configured as routers? Will I be able to use single SSID and switch among decos seamlessly?

3- Will all decos actively provide wireless network access to devices (like mobile phones, laptops, smart TV, ..)

@emrSn I think this will work fine, but I think if it fails as router configuration then try access point. My router config faile after 3 were set up, and when I set up as access point all six worked fine. Another caveat is that without cat 4 connection I felt needed to be in sight of next connection as k was going about 100 ft between two buildings

@TP-Link Deco 

Please Help.. i've already have 2 piece Deco E4 and now i want to buy Deco X20 as the main unit.

My Question is, with Dexo X20 as the main unit and Deco E4 as the second & third unit, can I still set up Ethernet Backhaul ? or The main unit must the same type with deco e4 ?

Thanks for your help