I've just installed a BT whole home wifi premium system with 6 discs (just bought it off BT online shop, so assume latest gen discs? & all running firmware version : SGAB20822C) and have the following setup - see below diagram (I'm no artist, so this is representative but not 100% accurate! 🙂 )
It's a large, old house with thick walls, so I'm using ethernet to connect the discs. Generally works well, though I'm noticing that some of the discs are "ignoring" the ethernet connection - specifically the one in the "garden office", which is ~60ft away from the house and has an ethernet cable running back to the house. I'm connecting all discs via 1st port to main switch (24 port gigabit unmanaged switch), and then any downstream devices to 2nd port (either direct or via a small gigabit unmanaged switch in that part of the house). Though curiously observing that the web admin console thinks port 1 = port 2 and vice versa!? Is that a UI problem, or are the ports labeled incorrectly on the discs?
Anyway, the disc in the garden office is too far away to establish a reliable backhaul connection over wifi, but in spite of having it hard wired, I'm noticing that it keeps polling (blue flashing light or amber light = poor connection) and trying to connect over wifi. As result, all devices in that garden office using wifi are connecting to one of the discs in the house with poor signal (-83dBm) and speed is thus suffering.
From reading the posts it seems like port 1 should be used to connect the disc to the switch that connects to the master disc, and then port 2 on the disc is for downstream devices to connect to that disc, so in effect creating a daisy chain topology. Is that correct? If so, why does the disc keep trying to connect over wifi when there is an ethernet backhaul available and thus refusing connections from devices <5ft away? Ps. I've tried reversing the ports and connecting discs to ethernet port 2, per the confusing web admin UI comment above, but that doesn't make any difference AFAICT.
A few thoughts :
I have a very similar set up, using 2 network switches daisy chained.
1) is the the diagram correct ? The second network switch should be connected by Ethernet directly to the first switch. The disc in the garden room should be connected into the second switch.
2) have you checked that the second switch is functioning correctly ? Eg Plug in a laptop using Ethernet to check internet connection.
3) Try restarting everything including the switches, starting with the router and working downstream from the router.
4) do you even need the second switch in the garden room ? If not try connecting the garden room disc directly to the first switch using the router.
5) if all else fails try to establish if the system works without any switches. Ie plug the discs directly into the BT hub.
can’t think of much else… good luck