@TP-Link Four years, 72 replies, 48 votes and counting. The only official response from TP-Link has been, "Tell us why you need this." Very many repsonses have told you why, yet there has been no other official response from TP-Link. Absolutely terrible customer service.

TP-Link wrote

@JLNL 

Hi, When Deco is on the access point mode, there is no need to set up VLAN tag on the switch to allow satellite Deco's guest devices to work properly;

The guest network and main network is not separated by VLAN ID on access point mode;

And When you choose ‘select Isolation form main network’ for the guest network under access point mode, the guest devices could only access the gateway;

 

So may I know why you need the VLAN tagging of the guest network?

Thank you very much.