Hello everyone,

I am a complete novice and I am completely lost between the different concepts of router, modem, network, virtual network, switch, etc. I would like to get two lans and two completely independent wifi networks. I have 3 X50 POE decos, a Zyxel GS1200 5HP switch and a BBOX fit box. Today I have :

Ethernet connection:

- connected via ethernet a main deco, to the box, then the switch to the main deco via the second ethernet port.
- 2 other decos are connected to the switch via ethernet and powered by it.

WiFi networks:

- WIFI A: network shared between the main decor and the second decor
- WIFI B: on the third decoration

The problem :

When a user connects to wifi network B, I have a notification on my phone (connected to wifi A) that indicates which program they are watching on the chromecast. I therefore imagine that all the devices connected to the switch, whether they are connected to wifi A or B, communicate and are part of the same network (in fact I have a little difficulty understanding the meaning of network because two members of two different wifi networks can visibly communicate via the switch...).

I tried to create a VLAN for deco3 (for wifi B) by removing the tag on port #1 (the port connected to the main deco) but deco 3 no longer had access to the internet :(

How can we ensure that both networks have access to the internet but are perfectly isolated?