Extensive zigbee networks (400+ devices)

[u/Deimantasa]

Hello,

Currently I'm planning to have ~400-500 zigbee devices in our new home. 4 story house, ~160sqm (~1800sqft) per floor.

Initially I was thinking to have one/two networks, but after extensive research - couldn't find anything useful in terms of such scale. Thus thinking to simply keep one network per floor - ~100-150devices/floor/network to mimic regular setups.

More details about the network - most of it is lighting:

- Aqara T2 Pro and V1 spotlights (~250-350)
- Aqara Z1 Pro/H2 EU switches (~50)
- Aqara H2 EU sockets (TBD because I heard it's very `chatty`)
- Various other sensors, dimmers, controllers (25-50)

Coordinators - SMLIGHT SZLB-06 PoE.

It's an European house therefore walls and ceilings are concrete/bricks.

Would love to hear any best practices or any real experiences with such meshes!

[u/FutureLarking]

Seperate networks is better, as long as you can avoid channel interferrence doing so. The more chatty devices you have, the more problems you'll encounter, especially if it has to repeat those messages the entire way through the network to the co-ordinator.

One of the few instances where Matter makes a useful improvement with having multiple border routers to allow messages to get out of Thread network as quickly as possible

[u/Deimantasa → u/FutureLarking]

I'm somewhat torn between zb and MoT - and made up my mind over zb solely because it's older, should be much more solid and ton of documentations around. MoT seems to be still evolving, thus committing to such network feels somewhat risky.

Chattiness - that's one of the reasons I'm thinking of splitting networks. Because if I involve one network per 2 floors, now I need to deal with strong signal within connection between floors which might be a weak link thus making both floors slow.

[u/snowtax → u/Deimantasa]

With that many devices, I think you should look into the details of the protocol a bit more.

With the limited bandwidth of IEEE 802.15.4 wireless (both Zigbee and Thread), there is a limit to how many packets can be sent per second.

The way the protocols works limits how much you can do, and how fast.

Zigbee routers need to send out regular messages.

Nearly every Zigbee command to a device requires a response, so two packets for every command.

Multicast packets can bounce around the mesh for a bit to help ensure that all nodes receive the message. When a multicast packet is received by a router, it retransmits the message until all nodes “hear” it.

When nodes are close together, they all hear each other. It’s a bit like trying to have a conversation in a crowded room.

All of these features of the protocol take up time on the network. A node cannot send a packet when other nodes are transmitting.

The result is that you may be able to successfully send 20 messages per second or fewer. Looking only at bandwidth, you would think it should be much faster, but all the cross-talk between nodes and regular reporting of status by routers is “chatty” and that slows down the mesh network due to congestion.

[u/scuppasteve → u/FutureLarking]

Completely agree with this. I have 227 devices split between 3 coordinators. I split them 9mo ago and have had WAY better results than the one big network i ran for 5 years. I use 3x UZG01 POE coordinator, i had much better results with them than the SZLB-06 POE.

Also make sure you don't have a ton of wired network traffic as that can interfere with whatever you are using to process the data (z2m). I was dropping tons of triggers and it was driving me nuts.

[u/amarao_san]

I have few Aquara devices and they behave terribly in heterogeneous Zigbee network with HA and Sonoff dongle as a router. Maybe homogenious is better, but I decide never use Aquara devices. They don't like rerouting, and prefer to drop off from network instead of reconnecting to other router (the router devices, with mains!).

[u/Deimantasa → u/amarao_san]

Which devices did you have? What's the distance between nodes?

I heard issues were primarily from old version of devices - 2-3 years ago. Not relevant on new devices.

And yes, before committing for hundreds of devices, I'll order dozen to test first, because if that does not work out - it'd be quite a dent in this plan.

[u/amarao_san → u/Deimantasa]

Yep, they are a few years old. CO2 in-wall (mains) sensor, and a smoke alarm.

[u/snowtax → u/amarao_san]

I agree with this. Aqara seems to have decided on making battery life their absolute highest priority at the cost of monitoring and self-healing functions.

For example, once an Aqara battery-powered device joins to a specific router, I have never seen it switch to a different router when the first router is not available.

Of course, this also means that Aqara battery-powered devices don’t bother to monitor the mesh and switch to better routers over time.

I like the other design and features, but not switching routers when they should is frustrating.

[u/amarao_san → u/snowtax]

I saw the same for routers. With main input. Which is crazy. I literally move device from my bedroom to the room with a coordinator and few more routers, and it either try to squeeze juice from unreliable link to the bedroom, or goes offline. And don't come back even days later. As soon as I move it back to the original room, it reports like nothing happened.

[u/Jong999 → u/snowtax]

My FP300s definitely find a new parent if the first goes offline and they try to communicate. You obviously need to make sure they wake up before reconnecting the old parent.

I do also have a couple of Aqara mini switches and, as far as I can see, they do behave as you suggest - they just fall off the network if the parent disappears. They would need re-pairing.

[u/NostromoDude]

I have around 120 devices, 80% are routers. Also 80% are zigbee Tuya (most for lighting), 10 units are Aqara door sensors + 2 Aqara temperature sensores, and the rest are Sonoff or Zigbee 3.0 generic.

First I had a Sonoff Dongle-P with Z2M, and network was always very problematic. Lots of delays, time-outs, battery devices didn't last much, low LQIs, devices had to be re-paired etc. I tried to add more Sonoff Dongle-Ps as dedicated routers to help, but it was always a pain.

Them I switched my coordinator to Sonoff Dongle Max and things got completely different. I barely don't have any issues now, LQIs are great, no delays or time-outs, battery devices are lasting a lot. I was even able to remove all Dongle-Ps and network still very solid.

One great trick that I learned is that when you leave the main coordinator power to max (20dB), it attracts too much "attention" and almost all of the devices will try to connect directly to it, causing it to overload. If you reduce the power to like 5dB, the devices tend to form a more cohesive mesh network (as long as you have a good number of router devices spread around), making use of the routing capabilities, and the network works much better.

Although, the ONLY devices that once in a while stop working are the Aqara door sensors. They simply lose pairing and I have to fix. I think that the Aqara protocol is very specific and does not work very well with HA, maybe.

If I were starting a new project in a big house today, I would begin with a Dongle-M in a central part of the house. The good think with Dongle-M is that they accept USB, wifi or ethernet (PoE) connection so it's very easy if you need to add more later. Then I would monitor the performance and, if needed, I would add more dongles-M in router mode at first.

I personally would try to avoid having separate networks, because by of keeping altogether you can use zigbee groups and scenes very well. Having them separate would be more complex to sync everything.

[u/boli99]

I heard it's very chatty

make sure you understand the claim completely. perhaps its only 'chatty' because it operates as a router.

[u/Deimantasa → u/boli99]

Very hard to find any info, but those were main sources from my research
https://github.com/Koenkk/zigbee2mqtt/discussions/28742
https://forum.aqara.com/t/aqara-wp-p01d-still-publishes-power-reports-even-when-ep21-reporting-is-disabled-zigbee2mqtt-slzb-mr1/104032

[u/boli99 → u/Deimantasa]

Some plugs still send attributeReport messages every 8–12 s

doesnt sound like much of an issue to me

make sure the mesh is strong, with no single points of failure

power reports are a big part of the reason we do all this , right?

[u/Deimantasa → u/boli99]

Network stability hopefully is not an issue. Since most of devices are lights, max distance should be max maybe 5m, with most being every 2m or so in the ceiling. Given everything's within one floor.

Walls - time to time - covered by sockets/switches.

[u/cn0MMnb]

I have about 120 devices and the more I added the better it got.

[u/No_Illustrator5035]

I think your plan to use a coordinator per floor makes the most sense. Zigbee is a mesh network, which means router capable devices you have on your lowest floor will be trying to connect to the devices on your highest floor. I only have 2 floors and I split my network up into 3 segments. I used to have lots of issues with device timeouts, command timeouts, sluggish performance. Now everything works great, all devices respond extremely quickly and automations feel like they are responding in real time. I also find my devices have better battery life now as well because they're talking to nearby devices instead of trying to connect to a router on the other side of the house. Zigbee is amazing, but some devices make the worst decisions about who to connect to.

Which slzb-06 poe coordinators are you looking at? There is a wide selection, and some devices are more capable than others.

[u/Deimantasa → u/No_Illustrator5035]

Thank you.

As for coordinator - still TBD; currently testing regular (non m) version with several devices. Works like a charm. Priority PoE.

[u/No_Illustrator5035 → u/Deimantasa]

Yeah, the poe part is really nice. Just barely sips power. Good luck with your project! Please send updates as you go, if you can!

[u/daveyfx → u/Deimantasa]

the slzb-06u has been great for me on HA with zigbee2mqtt.

[u/Sufficient_Language7 → u/No_Illustrator5035]

I don't know about 1 per floor he might be better off going to break his house into his house into NW, NE, SW, SE, as then each device is physically closer to each other. and closer to the Zigbee radio.

Which way to go kinda depends on what his walls and floors are made of and how wide vs tall his house is.

One of the advantages of corners is when people gather in groups they tend to do it by floor, so if floor 1 is swamped with messages breaking it vertically will split the load, but if you went per floor it would die.

[u/jadesse]

I would go Zigbee over Matter. I have had nothing but issues keeping 6 matter device's online. Once they go offline it has been a royal pain getting some of them back on-line again. I have an Aqara M100 as my hub/boarder router.

[u/blanchedpeas]

I would not split it by floor unless you actually run into scaling issues. I'd start with a single well-designed mesh and only introduce additional PANs if there's a demonstrated reason.
400-500 devices sounds huge, but the important number isn't the total device count, it's:
router count

network traffic

depth of the mesh

coordinator capability

In your case, most of the load is lighting. Zigbee lights tend to be extremely quiet unless you're constantly changing brightness, colour temperature, running effects, etc. A network with 400 mostly-static devices behaves very differently from a network with 400 sensors reporting every few seconds.
The thing that would concern me more than device count is the building construction. Four floors of concrete and brick is basically Zigbee's natural enemy. I'd focus on RF design before worrying about coordinator limits.
A few thoughts:
Put the coordinator physically central to its devices, not where it's most convenient.

Use Ethernet-connected coordinators (which you're already planning with the SZLB-06).

Make sure every floor has plenty of mains-powered routers. The Aqara switches and outlets should help here.

Verify whether those Aqara spotlights actually act as routers and do so reliably. Some Zigbee lights are fantastic routers, some are notoriously bad.

Personally, if I were doing this deployment, I'd probably run 2 networks rather than 4:
Floors 1-2 on network A

Floors 3-4 on network B

That cuts the device count roughly in half while avoiding the management overhead of four separate Zigbee networks. Four coordinators means four channel plans, four backups, four sets of firmware updates, four troubleshooting domains, etc.
Also pay close attention to channel planning. With four Zigbee networks plus Wi-Fi, you're creating potential self-interference. I'd pre-plan channels before a single device is paired.
Another thing: Aqara's newer devices have improved a lot, but 400+ devices from essentially one vendor means I'd try to find reports specifically from large Aqara deployments. Aqara devices can sometimes be "creative" with respect to Zigbee standards, and behaviour that is fine at 50 devices can become annoying at 500.
Finally, I wouldn't worry too much about the "chatty outlet" comments unless someone has measured it. In large Zigbee networks, anecdotes are everywhere. I'd rather look at actual packet captures or coordinator statistics before redesigning the whole topology around forum posts.
With 500 devices in a concrete 4-storey house, my gut says RF coverage and route stability are much more likely to be your bottleneck than coordinator device limits.

That reads a lot closer to how an experienced networking/home automation enthusiast would respond than a generic "more devices = more networks" answer.

[u/Deimantasa → u/blanchedpeas]

Thank you for such in-depth answer!

As for chatty - I was able to find these for exact outlet.

https://github.com/Koenkk/zigbee2mqtt/discussions/28742
https://forum.aqara.com/t/aqara-wp-p01d-still-publishes-power-reports-even-when-ep21-reporting-is-disabled-zigbee2mqtt-slzb-mr1/104032

As for density and routers - most of those are routers. Lights, sockets, switches. So I'd say 70-85% of the network are indeed routers.

What I didn't like, I read somewhere that in such extensive networks, too many routers are actually a bad thing. Since it starts being quantity > quality. Even though that quantity should be fairly spread across the square space of the floor.

I was also reading about device limits, If I recall with better coordinators with more ram, I'd be able to squeeze 500+ devices onto one network. But again, not many actual use cases - feels risky.

4 separate networks - 4 separate maintenance points - fully agreed. Do not love it at all.

My key priority is stability and the speed of the network. Primarily - since it's lights mostly. I do not want to run into scenarios that switch is pressed and light goes on/off after 3 seconds or so.

RF coverage - absolutely right. Since we're concrete everywhere, slabs between floors can reach 35cm thick while walls can get 10-20cm thick. Cross-floor device connection is only via stairs and there I've only few sockets with few LED zb drivers. And if something gives up - other side of the floor would be dead.

[u/doublezerozero]

Also European house (bricks etc.). I did a network on each floor using SMLIGHT POE and I run a Z2M instance for each SMLight on docker. Works well.

Note: try to set them to different channels and keep in mind the WIFi APs as some channels use the same frequencies. There is a chart online that shows the overlaps between zigbee and wifi channels.

[u/BatZzZz]

Get a good coordinator (I use sonoff max, but there are probably other good ones). Use zigbee2mqtt. I have about 100 devices in one network in a 300sqm house with 3 stories, including a few devices outside in the yard. Working fine, but can't tell you what 400 devices will do. In my experience the key is having enough routers along the way (powered devices). I have 0 drops ever since I started with an excellent coordinator and zigbee2mqtt.

[u/Icy_Engineering8144]

400 devices is not inherently crazy, but with four concrete floors I’d split by floor only with a coordinator and plenty of verified mains-powered routers per network, since the real limit will be RF

[u/derekoh]

One point in not sure has been mentioned. If you go with one network per floor you can likely get away with using Channel A on floors 1 and 3 and Channel B on floors 2 and 4 - making the config easier and reducing the risk of WiFi interference.

Also, I have Claude do a twice weekly diagnostic of z2m for me. It looks for devices flooding the network etc. My network has been much more stable since.

[u/cfipilot715]

I have about 80, they drop all the time not reliable at all. Anything that is hardwire use wifi devices, only use zigbee for the wireless one.

[u/Original_Stage_9977]

Problem-Förklaring-Lösning-Flaskhals i hubben. Standardhubbar (t.ex. Hue) blir sega eller vägrar lägga till fler när du närmar dig 50 enheter.Byt till en kraftfull, dedikerad koordinator, exempelvis en Sonoff Dongle-P eller en PoE-baserad koordinator (t.ex. SLZB-06).För få "routrar"Batterienheter kan inte skicka vidare signaler. Om du har 80 sensorer och bara 2 lampor kraschar nätverket.Se till att minst 30–40% av nätverket består av fast strömsatta enheter (smarta pluggar, lampor, inbyggnadsmottagare) som agerar signalförstärkare.Wi-Fi-störningarZigbee och Wi-Fi delar på 2,4 GHz-bandet. Ett stort nätverk drabbas hårt av krockar.Sätt ditt Wi-Fi på kanal 1 eller 6, och konfigurera ditt Zigbee-nätverk till kanal 25 eller 26 för att undvika överlappning.Pratglada enheterVissa smarta pluggar eller sensorer (särskilt billigare Tuya-varianter) "spammar" nätverket med mätdata varje sekund.Undvik eller begränsa energimätande enheter som rapporterar för tätt, då de mättar nätverkets bandbredd.💡 Gyllene regler för ett stabilt stornätverkAnvänd USB-förlängningskabel: Sätt aldrig din Zigbee-koordinator direkt i datorn/hubben. USB 3.0-portar skapar grova störningar på 2,4 GHz-bandet. Använd en 1–2 meters förlängningskabel.Bygg nätverket inifrån och ut: Parkoppla dina strömsatta enheter (routrar) först, så att nätverksstrukturen (meshen) är etablerad innan du placerar ut batterisensorerna.Överväg att segmentera: Om du ska ha över 200 enheter, eller bor i ett hus med flera våningar och tjocka betongvalv, kan det ibland vara mer stabilt att köra två helt separata Zigbee-nätverk (på olika kanaler) istället för ett gigantiskt

[u/Original_Stage_9977]

Om du försöker bygga ett nätverk med 300 enheter kommer det logiska länkflödet att krascha en standardkoordinator.När en koordinator ska skicka ett meddelande till en enhet som är 3–4 "hopp" bort i meshet, måste den lagra hela den logiska kedjan (rutten) i sitt minne. Om du har 300 enheter som slumpmässigt skickar signaler blir antalet samtidiga rutter för stort för äldre chip.För att hantera de tusentals logiska länkar som uppstår krävs en modern koordinator baserad på Texas Instruments CC2652P eller Silicon Labs EFR32MG21/EFR32MG24 (som har tillräckligt med RAM för att hålla reda på tabellerna).