Multiple hubs, device limits, zigbee/wifi network interference

Devices & Integrations Connected Things
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Hi everyone. As you may have read in my posts over the last few weeks, I very recently fired up my SmartThings hub again after taking a break for awhile and playing with other platforms.

A big part of this, for me, is that I have slowly been pushing my home towards Matter, as much as possible. If I already have a ton of stuff connecting over Matter, why not connect them to ST as well? It can only open more possibilities!

But what I didn’t anticipate was after making the Matter connections with my V3 hub, along with adding the associated drivers, I was already pushing the device limits for said hub. And that was before adding the small zwave and zigbee networks I had been planning on incorporating in to ST.

After doing some research, I decided on a plan. Add a ST Station to a hub group. The V3 hub would handle the Matter and zwave network (around 20ish devices) and corresponding drivers. The Station would handle the zigbee network (40-50 devices) along with any Thread items I end up adding (not planned at the moment, but you never know) and their corresponding drivers.

Two issues I discovered: for a zwave network to work, the hub that controls zwave must be the primary hub AND when attempting to pair a zigbee device, it will add to whichever is considered the primary hub. Meaning in a hub group environment, I could not use the Station as the zigbee controller.

So I turned off the hub group and separated them. This way I can choose which hub each device I want to add will go to, this achieving the goal I stated above.

Does this make the most sense? Or does the hub group manage this automatically? I guess what I’m saying is does the hub group increase the device limit so that when the primary gets filled up, devices added to the account automatically get added to the secondary hub? Or is the answer door #3 - I’m way off base and approaching this all wrong?

Additionally, I’m trying to be conscious of zigbee interference, both with other zigbee networks (hue, aqara, ikea…don’t ask) and with wifi. So if I am not intending to use the zigbee or thread radios in the V3 hub, could they be disabled so they aren’t sitting out there on a channel but not doing anything? I am more than likely going to change the zigbee channel the Station is using since it is the same as the Ikea hub and that one can’t be changed, to my knowledge. Do I need to change the V3 accordingly if I can’t turn it off?

Also if zigbee channels 11, 15, 20, and 25 are all in use :flushed: …what does that mean for wifi?

Oh and is there still a master list of drivers somewhere? I seem to recall a wiki link at some point but I can’t find it now. I’m particularly interested in those provided directly by the manufacturers, like Zooz and Third Reality have done.

Thanks!

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As far as I can tell from what’s been published so far, the hub group just adds all new devices to the primary, and it doesn’t increase the number of edge drivers you can use, and it doesn’t let you separate devices, as you noted in your practical attempts.

Looked at architecturally, it appears to me to be working basically like the Samsung Wi-Fi mesh multi hub networks worked. It is not working the way a typical Z wave multi hub network works (but then SmartThings never has) and it does not work the way a thread fabric works. It’s basically a primary with some subs.

If somebody knows more about it than that, hopefully they will post.

But for now, given the issues you’re trying to address, I do think not using a hub group would make the most sense for you. Then you can have specific edge drivers on each hub and add specific devices to them.

If all the hubs are in the same location, it won’t increase the total device limit in the app, though, you’re still going to be stuck with that.

I’m going to tag a few people who I know do have practical experience with multiple hubs in case they have something more to add.

@Automated_House @csstup @orangebucket

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From previous discussions, in a hub group, one hub is primary and handles all device pairings, message processing, etc. The secondary hubs are simply radio repeaters that extend the range of the various radio types. If you are hitting memory limits, a hub group won’t help.

I’m surprised the OP is having issues with so few devices on the v3 hub, though, I’m not sure what he meant by “device limits”. As you point out, there are limits imposed by the app that have nothing to do with the hub itself.

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So the device limit is coming from the app itself? That might be a problem…

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How many devices do you have in total? I have well over 100 and have no issue with device limits.

I don’t remember if the app limit is currently 200 or 300 devices per location.

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Ok so I may not be thinking of things the right way. That’s very possible. But before I was starting to change things around, when adding a device I was getting “hub almost full” warnings. I took that to mean there was a limit on how many devices that could be added to each hub.

And because of hue/ikea/aqara/switchbot and some one-off devices, the number of Matter items I have added is already well past 100, Probably at least 125. Then I also added some cloud connections like Bond, Lutron, etc. Plus drivers. And all of that is before I bring in the zigbee and zwave stuff I mentioned earlier.

And I had added some zigbee/zwave related drivers in anticipation of the next phase of this so those would have been sitting on the V3 hub as well.

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Ah after reading another thread, it sounds like the “hub almost full” error is related to the number of drivers on the hub.

So that means adding the second hub and dividing the drivers more evenly should prevent any issues like that. Also means I have two sets of JBL, Bose, Samsung, etc drivers counting against my total :-1:

But I’m getting somewhere now in terms of my understanding of all this!

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There are multiple limits you can run into.

The app has a limit per location. Not per hub. It’s changed from time to time, sometimes been 200, sometimes been 300, sometimes been different on iOS versus android. To be honest, I’m not sure exactly what it is right now. But it has to do with the device lists in the app, so everything counts against it that has a device tile.

Some of the protocols have a limit, such as Z wave, which is limited to 232 devices per network for the generation that SmartThings uses (fifth generation, or series 500). That number does go up significantly with series 800, but there are no SmartThings compatible hubs that use that yet.

Each hub is limited to a max of 50 edge drivers. I’ve seen it written both ways as to whether the stock provided edge drivers like for Sonos count against that 50 or not. :thinking:

Each hub also has a memory limit that only applies to active edge drivers. So if the Sonos edge driver is on your hub, but you don’t have any Sonos devices and you aren’t using it, it won’t count against the memory limit. For the memory limit, you will get warning messages that you can see on the advanced page of the official web interface to your account:

My.smartthings.com/advanced

It will say if the hub is at a “soft limit“ or “hard limit.“or “ok.”

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They don’t count as long as you don’t have those devices. Drivers are loaded on demand and having them installed doesn’t mean they are in memory.

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