HA Matter issues when mixing Border routers of different brands

Configuration Matter/Thread
1

I have multiple Matter over Thread devices.

I have 6 border routers
3x nest hub
1x nest hub max
1x google tv streamer
1x OTBR on hom assistent.

As long as I don’t enable OTBR, I have no issues. The HA Matter network is rock solid and very stsble (days/weeks/months) then. After enabling OTBR and after some time (minutes/hours devices becoming unavailable. Especially my nanoleaf bulps, but also others. I think it is a HA matter issue. Why I thinkthat? I also added all my mattter devices in Google Home and there they are always available. Even on the moments they are unavailable in Matter on homeassistant.

Then I got myself Aqara M3 hub. This device also is border router. After adding it to my Thread network my devices again becoming unavailable in HA matter while in Google Home they are available and working.

It looks like when mixing thread border routers from different brands the HA matter server gets issues.

So for now I disbaled the OTBR and Aqara M3 hub.

But the thing is, I need the OTBR. It supports nat64 to remote acces my Nuki 4 pro via the Nuki app. The nest border routers don’t support nat64. Also my OTBR is placed on central place for good thread coverage for some far away devices, but I can’t use of the issues.

2

I think there is a limit of 5 border routers per network and sometimes there can be differences in the standard they follow, which might cause issues too.
The HA Matter service is generally far ahead of the other brands.

EDIT: I found here that the standard say 32 routers in a network, but I read somewhere else that it was only 5. Maybe some of the brands have lower limits than the standard.
https://openthread.io/guides/thread-primer/node-roles-and-types

3

Can you point where this limit is documented. If there is is a limit is doesn’t effect Google’s matter implementation. In Google home I get a stable matter network even with 7 border routers.

4

I have seen some issues like this on Discord. Here is one thread that maybe of interest.

5

I don’t have an answer for you, other than you’re not the only one experiencing routing issues with multiple TBRs. I believe there are several GitHub issues.

This is referring to routing nodes, not border routers. Afaik there is no limit on TBRs but there is also no benefit in having lots of them. Your LAN devices will just see lots of next-hops to the thread subnet and have to pick one; if it goes down they pick the next one.

You can try making a separate Thread mesh just for the OTBR and devices within its range, you don’t need to merge it with the Google mesh. You do need to make it your preferred network because the HA app is the only app that can commission to the OTBR mesh (the Google Home app can continue to commission to your Google mesh, and share to HA).

6

This is exactly the issue I have. In my case it is probably a HA Matter issue and not an unhealthy thread network. I have two reasons for this thought. Some devices that get unavailable are in line of sight of 2 meters from te closest border router.
Second. The same devices in Google home always available en working (tested)

I already thought about this. The thing that makes it complicated for me is, I cannot clear the thread credentials on my phone. Tried clearing playstore data etc. Never worked. This means I can only add devices to the current thread network. I this case the Google network. So when I add a second thread network for the OTBR I cannnot add devices to this network.

7

I was an early adopter of Matter on HA.
Had no real issues with Matter except bad firmware on devices in the early days.
Had enormous problems though with thread until I threw SkyConnect in the bin and removed OTBR from HA.
Network is rock solid with four Google nest hubs an an Apple Mini.
Only issue I have these days is the awful Eve Home Door/Window sensors.
Other Eve devices are fine and Aqara P2 door sensor is fine.
Nanoleaf Essentials downlights are good as well.