A zigbee routing question


#1

(from a future post called: "Confessions of a Z-Wave Fan Boy")

It appears that the only way to get Hubitat to recreate the entire Zigbee network (after adding/removing many devices) is to take the Hub down for a substantial period of time (perhaps greater than 30 minutes? - to get each device to recreate the optimal mesh path to the hub).

Is that correct?
I know that I don't have to do that on a regular basis, but isn't it helpful after adding/removing many devices? Have other people found it to be necessary?
Is there a way within Hubitat to do that?
I suppose I could manually just do a shutdown, and bring it back manually.

Any other suggestions?


#2

I have never had a need to force a Zigbee mesh rebuild. I believe Zigbee automatically optimizes/heals itself.


#3

The Zigbee mesh will rebuild itself over time and regularly does. The shutdown/restart procedure is just a method to kickstart the rebuild.


#4

Any idea of the timeframe for "over time"? Is that a HE parameter, or a zigbee parameter?


#5

You really don't need to do anything here. A Zigbee network is constantly rebuilding and updating the routing tables. Sleepy end devices connect to a router. If that router is "lost" (e.g. power outage) the end device will connect to another known router.

Let's ask the question: Do you have a problem that you are trying to fix? Most issues with Zigbee come down of not having enough routers in a network. I say most, not all. That's why I asked the question.

The force healing (turn off hub for 20 minutes) usually only kickstarts the process. It doesn't mean that it is completely done right away. It can take more than 24 hours until the network healed itself again once you kickstarted this process.

EDIT: Oh, and there are no parameters anywhere to adjust...


#6

This may be helpful. Read the section 4.3 regarding route discovery and route repair.


#7

True. And this is why I cringe every time I read, "I paired my zigbee device right next to the hub and moved it back...":smile:


#8

I have a Zwave fan controller that is about 5 feet from the Hub both in the same room. One would expect that that would connect directly to the Hub. Two hops away I find out. On the same side of the room, there are a whole bunch of 2x4 and 4x4 posts between them.


#9

(Again, from "Confessions of a Z-Wave Fan Boy"):
I have noticed in a number of situations, a high degree of variability in terms of Zigbee sensor/switch response. That is, sometimes a Zigbee switch will respond instantly, and sometimes after some delay.
Is that due to a Zigbee mesh that hasn't yet "settled down"?
Is that due to some slowdown on the Hubitat side?
Is that due to some issue with the particular Ziogbee switch/sensor?

P.S. I have been reading extensively about Zigbee networks and mesh structure concepts (I plan on publishing at some point in time "Confessions of a tired Network Engineer" ...). Sometimes, the lack of extensive network design tools, (Zigbeee/Zwave instead of my trusty Cisco suite), drives me crazy! I feel like I'm blind, leading the blind!)


#10

It is all about signal strength... If the other signal is stronger and is reliable, it will chose that path. That's also why it sometimes does make sense to have dedicated Zwave repeaters as they amplify the signal too


#11

The best Tool for a Zigbee network is an Xbee. This really let's you "see" why you have an unreliable network. I would bet that one of the two is true:

  • the device in question has a low LQI
    or
  • the router that is nearby has a full routing table (too many devices trying to connect via that one router)

#12

Also, I'd like to make a plug (pun intended), for the TradFri Zigbee repeaters that are available at Ikea. Very inexpensive, and seem to work very well!
https://www.ikea.com/ca/en/p/tradfri-signal-repeater-30400407/


#13

The secret to zigbee is repeaters. The simple math is essentially 1 repeating device for every 6 sensors. This way you should be safe.

Then obviously, placing them in between sensors and other repeaters.

Unlike zwave, you can't have too many repeaters.


New to Hubitat (and zwave/zigbee)
#14

Or use Xbee's as repeaters and you can go up to 14 (or 19 with the Pro version) :slight_smile:


#15

I do happen to notice that the Hubitat implementation of Zigbee networks seems to be somewhat more flexible than others (specifically, you know who).
Perhaps that's also another competitive advantage that could be emphasized more.

That comes to the fore, because here (the Great White North, but perhaps elsewhere), many Zigbee devices are half the cost of corresponding Z-Wave devices. I'm talking not just about sensors, but also switches, too. That kind of difference in cost, makes you take a second look.


#16

If xbee would just sell a house, pet friendly, model I would buy more if them. My cats would destroy an unhoused xbee in 5 seconds.


#17

I actually just ordered similar parts as shown here to make my Xbee's a bit more "house friendly"

Not sure how "cat resistant" it is though


#18

Could be any or all. I will go on record as being a Zigbee fanboy. When the mesh is healthy, the speed is sooo much quicker than z-wave. I'll also admit that it took a little work to optimize my zigbee mesh. I started with getting Xbees, to provide visualization and repeaters, and quickly saw just how detrimental repeating bulbs are. End devices love to repeat through bulbs, but the bulbs just can't handle the quantity. Replacing Crees and Osrams with Sengleds (which do not repeat) put me on the right path. Two Xbees and six Tradfri outlets provide more that enough routes around my house for the dynamic nature of zigbee. FWIW, from an Iris V2 motion sensor detecting motion to an old GE z-wave (non-plus) switch turning on, it takes about 200 ms. I'm happy with that.


#19

Sure, any repeater can have a larger route cache and be configured for more than 6, but considering most repeaters are defaulted to 6, its a good practice.

Obviously, this isn't a hard rule, since the hub can support many more direct connected devices. But many people forget that Zigbee (and Z-Wave) are mesh networks. Mesh networks require repeaters and the routes to be rebuilt, which happens over time.

Pairing in place is the easiest way to make sure you don't have routing issues. If it can't pair in place, it probably means you don't have enough repeaters or your repeater routing tables are full.

I just wish someone made a decent replacement outlet in-wall that did zigbee. For my house, since I did Lutron Dimmers and Switches, I put Zigbee plug in outlets in every room and hallway I could to get my repeater count up and all of my boundary sensors are zigbee and work great. Doors, windows, motion sensors, etc.

When I first did this, zigbee locks were only in the realm of control4 (actually had a few, but they failed, either touch screen or gears) and Z-Wave was the only option for DIY. So I also had to add a bunch of Z-Wave repeaters.

Anyway... Don't overthink Zigbee, its a self healing, mesh network that likes to have repeaters. Z-Wave has a 4 hop max and a 232 device limit... Zigbee doesn't. Go nuts, add repeaters. Just stay away from most Zigbee bulbs, they make bad repeaters by design... Bulbs are typically on switched outlets, someone will turn it off, unscrew the light, etc... Since I created two meshes, one for my bulbs and one for my sensors, my 230+ device network(s) have been pretty rock solid...


#20

I lost one to a cat and used what I had at hand to protect the others.


That's the box a Xiaomi leak sensor came in.