So I have been using Home Assistant for a few years now on a Home Assistant Blue. It has basically no native connectivity besides Ethernet. Until just recently, all I have used is Zwave and WiFi devices. For the Zwave I had an Aeotec stick that has been getting slow and a little glitchy lately. I had a ZBT-1 plugged into the Blue but had no devices on it. Recently, I have begun to acquire both Zigbee and Matter/Thread devices, both of which I am new to. I just purchased a ZWA-2 to replace the Aeotec and it is working well. My question is about the ZBT-1 and ZBT-2 devices. When I set the ZBT-2 up I made it my new Matter/Thread device and then reconfigured the ZBT-1 for Zigbee. The last day or two I have been second guessing this decision. Since the Matter/Thread protocol is WiFi/IP based and from what I can tell does not use the antenna of the ZBT-2, would it be a better use of the devices to switch them around? Does the ZBT-1 have the horsepower to run a large Thread/Matter network if I continue to expand that protocol? Should I just get another ZBT-2 and let the ZBT-1 retire?
First, Thread is not WiFi-based, it’s unrelated. It is indeed an IP network, though. So, the only thing in common between Thread and WiFi is that these are both wireless networks using the IP protocol. On the lower level, Thread is way more like Zigbee (devices form a mesh).
Second, Matter, as a higher-level protocol, runs on top of whichever lower-level network protocol lies beneath (usually Thread, WiFi or Ethernet), it really doesn’t care what that protocol is, as long as it’s IP-routable. Technically nothing (maybe except sanity) stops you from running a Matter-over-IP-over-Avian-Carriers system.
Your ZBT-2 does not do Matter at all. Your main Home Assistant device is the Matter controller if you’re running the Matter server on it. It then controls commissioned Matter devices that it can get a route to, no matter (pun not intended) how it gets that route.
Your HA device connected to a ZBT-2 in Thread mode and with OTBR installed, becomes a Thread border router. Obviously, the antenna of the ZBT-2 then becomes the antenna through which Thread devices (be they Matter-over-Thread, Homekit-over-Thread, some-other-proprietary-protocol-over-Thread) connect to your system.
If I had both the ZBT-1 and ZBT-2, I’d use ZBT-2 for the network that is larger and/or more spread out (due to the larger antenna), and ZBT-1 for things that are closer and/or fewer. If these criteria don’t matter (a smaller house/apartment, roughly similar number of devices for each protocol, similarly spread out), I’d use ZBT-2 for Thread and ZBT-1 for Zigbee.
