The Deco Ethernet backhaul feature is based on the standard IEEE 1905.1 protocol. some D-Link switches (eg: d-link go-sw-8G) will not forward packets based on IEEE 1905.1 protocol, causing all Deco units in a network loop and becoming quite unstable. If you have a D-Link switch and encounter an unstable issue with Ethernet backhaul, recommend to change the switch to different brand or get D-Link support.
IEEE 1905.1 is good protocol to make the network better and easy.