@Lanieuwe 

Hi,

Thank you very much for your time and patience.

For your case, you could try the following suggestions:

1. Keep the ISP Ziggo router as the main router connected to the modem;
2. Set up all the Decos and Archer C6 as the access points;---in this way, the 6 nodes are nearly the same and we could swap their location easily;
3. Put each Archer C6 to where more Ethernet ports needs, and put all 3*S4 on the same floor which has the most mobile devices;

The simplified structure is like the following picture:

(There is one more additional Archer C6 and you could connect the other 5 nodes first, and if there is still a Wi-Fi dead zone, we could consider adding the last C6 back. )

Thank you very much and wait for your reply.

@Lanieuwe 

Hi,

The above connection map will work fine.

---the configuration is acceptable;

---as for the C6-2 and 3, please try to set up as the access point as well, then turn off the Wi-Fi and work as a 4 ports switch;

(if they are on the router mode with Wi-Fi off, there would be 2 different IP ranges, so the devices connected behind the C6-2 and 3 would have some issues when communicating with other home devices;)

How to set up: please log into the Archer C6 and go to advanced>operation mode> choose access point mode;

--if the Ziggo router has bridge modem mode, you could change to this mode directly and no need to turn off the Wi-Fi;(if not, you might need to turn off the Wi-Fi and turn off the DHCP server as well, since later the Archer C6-1 would be the router and work as the DHCP server.)

Thank you very much.