XBee3 router unexpectedly leaves network

XBee & XBee Gateway
1

Hi! I have a problem with two of my XBee3 devices. They occasionally stop communicating and leave the network, even though network watchdog is turned off (NW=0).

I did some sniffing. It communicates normally for a while, then suddenly sends a rejoin request. The coordinator approves it, then XBee3 sends several Many-to-One Route Failure status messages, then several Route Requests to the coordinator (dst: 0x0000), then it leaves the network.

I can’t figure out a reason why it suddenly decides it doesn;t have a route to the coordinator, and why it leaves the network. My understanding is that it should never leave the network on its own.

Note that it only happens on my ‘live’ network, which has about 40 devices. Both my Xbee3 devices have this problem. The test devices on my ‘test’ network with the same firmware seem to work correctly.

What can I do to investigate it further?

2

This sounds like you are having some ZDO issues with frames that are being sent by a device that is not expected or are incorrect.

I would suggest using a Zigbee sniffer to see if you can see what is gong on over the air.

3

I have the sniffing dump but couldn’t find anything interesting. The only reoccurring pattern involving XBee’s address I explained above. What else should I look into?

4

What firmware version is installed on your xbee models?

5

It’s 1010 (newer firmwares have issue with micropython bundling).
But I think I’ve found the problem. One of the third-party nodes was sending malformed rejoin responses, I have moved it to a separate network.
I am still not sure why it was leaving the network, but it seems stable now.