Interesting paper here (from the early days when Zigbee was new) that goes into schemes that were considered to categorize the reliability of an 802.15.4 radio link; it describes LDR (link delivery ratio) as the measure of the most reliable path. Packet based (tracking frame resends) and RSSI based (raw signal strength) approaches each have pros & cons; RSSI can include noise and multipath that muddies the result. Packet based techniques are slower to reflect changes in the RF environment.
Net of it all is that Zigbee settled on link costs to designate paths with lowest probability of resulting in retransmits. There is nothing in the spec that determines how LQI gets computed, but (however it is derived) it's an internal measure used to come up with the additive 'cost' numbers per hop that get advertised to other devices and compared when giving one route preference to another.
No telling which approach C-8 or C-7 is using (that would be speculating) but they're most likely different. Otherwise the 'lousy' C-8 LQI's would be matched with correspondingly higher cost numbers, and from what I've seen, they're not.
I thought that the info on the Zwave and Zigbee Details pages are values from the Z-radios, not hub calculated. I thought LQI and RSSI came out of the API from the radio. Potentially that would explain the different results we see now with completely different radio chips.
If by radio you mean SDK/stack that's my understanding as well. RSSI is derived from radio receiver. Bottom line, only the cost figure is intended to be 'on the same scale' among different Zigbee devices.
Don't know about Z-Wave; AFAIK RSSI measurement was an add on to later series Z-Wave (probably 'Plus' and later). Whether or not it is present depends on the SDK vintage of the device.
I'm on latest firmware C8 (and have tried several FW versions). Retarts, reboots, channel changes.... result is the same cannot pair zigbee devices which are on the habitat driver list and compatible.
You're not alone. A fair number of folks are having issues with a variety of devices. I have seen some stability with .121 but others are still having problems. Some folks (including me) are also reporting problems with Z-wave.
Is this your first hub or did you migrate from a C7? What is your zigbee power setting on, and where is your hub located relative to your router or nearest AP?
I'm glad I'm not having your issues. It's torturous watching your threads. Wish we could figure out what it is. I just paired 2 Neo coolcam water sensors and a gas sensor yesterday and they paired right up and are solid on the mesh.
i'm new to habitat with c8 - as had read about some connection issues and that's often a problem in my older house - my hub is connected by CAT7 straight to an orbi mesh access point and signal seems excellent.
I still think given you've had multiple hubs that something else is fundamentally wrong with your environment and not the hub(s) itself. I don't know what though...
Could very well be. I thought I had it with that PoE splitter but alas no. And it all worked fine on the C7 for a looooong time. I haven't added any net new devices. And everything I've migrated backto a c7 is working 100%.
In earlier versions there were hubs set to use the wrong zigbee stack which caused a lot of issues including not being able to pair. I believe .121 corrects that issue and forces the hub to use the correct stack.
I'm having Zigbee issues with the new C8 as well, but only with Aqara device (Door and Window Sensor). Did a test today pairing one with the new C8 (Channel 20) and one with my old C5 (Channel 16). After 6 hours I checked and the C5 is still talking to the device with no issues. C8 will no longer communicate with it's Door Sensor. Running Firmware 2.3.5.121 on both devices
I have 121 on 2xc7 and 2xc8. Now can’t pair any zigbee devices. There are a lot a threads out there with the same issue. Have back levelled one of the c8’s and now I can pair again. Not so on the c7’s that were stable and working prior to latest updates.
Not a good position. I brought 2 c8’s to upgrade to and they are sitting there not used.
Can’t do anything with C7 ‘s as cant add zigbee and scared to mess too much as if I bugger something up the core automation for the house is down.
Will be back levelling other c8 tonight to see if I can get the pairing working.
I've seen other similar posts of users w/C5s having better luck w/Aqara (which are not officially supported) contact sensors, etc. I have been very lucky recently w/Aqara contact sensors and buttons...contact sensors have been solid on my C8, of three buttons I just added, one fell off and had to be re-paired, but the other two have been fine. I've had enough trouble w/Aqara contact sensors on my C7 (though recently leading up to my migration from C7 to C8 they had settled down pretty well) that I don't consider them a device I can rely on for important notifications/rules. The only Aqara sensors I trust 100% at this point is the ones I have on Home Assistant connected via a Conbee Zigbee USB dongle. Those are rock-solid for many months.
ok, we have verified that sonoff devices, well for sure the sockets anyway are having a join issue with 2.3.5.121, we're looking into a specific fix for those.
They should stay functional on 2.3.5.121 after being joined on 2.3.5.110 and earlier.
118 through 121 include fixes for hue device joins as well as devices rejoining on their own so its best to run 121 after getting the sonoff devices joined.
