I have an Aeotec Range Extender 7 that I am using to reach an Aeotec Window/Door Contact Sensor 7 on my mail box.
Both devices are indicating this as their route in the IDE (With exception of “This Device”):
Route [This Device (2B) ]↔ Unknown Device (03) ↔ [Thermostat (20) ]↔ Unknown Device (03) ↔ [Center Lights (12) ]↔ [Home Hub]
There is no device (03) in the IDE furthermore the route loops back through it.
Anybody seen anything like this?
Thanks in advance.
What model hub do you have? And specifically are you using one of the smartthings Wi-Fi mesh systems with subhubs? Subhubs sometimes show up as unknown devices.
Otherwise that might be a ghost device and the message is trying to go through it, it’s not responding, so it’s having to try again with a different route. I believe that’s the most common reason for a device to show up twice in the message route. Device A tries to send through the ghost, it fails, so it sends the message to device B. Device B then tries to go through the ghost, and the message fails again, so then it gets rerouted.
Have you tried running a zwave repair to see if you get any details from that? 
I am using a version 2 Hub, no mesh, no subhubs. Now that being said, I do have two other hubs operating in their own network on the premises. I have performed a Z-Wave repair many times to no avail.
Thanks for the reply JD… JT here…lol
Thats a ghost. Your hub (firmware 37 and greater) will try to automatically clear them out but it may take a few days… ZWave repair does not.
Do a quick search for remove ZWave ghost and you’ll fimd many posts with the process to get rid of it.
Thanks. There seems to be no method to the madness when it comes to the Z-Wave routes.
I will sit right…
Thanks
I removed all Aeotec Range Extenders as they were causing more trouble then helping. i have an electric plug-in plug just inside my garage that the mailbox device uses as a repeater.
The routing is pretty logical. If you reset a device without deleting it from the network tables, or if you have a pairing which fails partway through, you end up with an entry for a device which no longer exists on the network. That’s a ghost.
The problem is that since it’s still in the network tables, other devices will keep trying to use it even though it’s no longer there.
So you just need to get the network tables cleaned up, and then everything should be fine. 
Thanks JD…
Actually I was referring to the devices other devices choose to make its way back to the hub. I have placed repeating Z-Wave devices in the shorter, more logical routes. Yet devices hop over them and choose longer routes. Drives me nuts…
JT
First, remember that the only thing that smartthings shows you is the most recently recorded route. It’s not the only route, nor is it even necessarily the most frequently used route.
The routing algorithms for Z wave are fairly complex and take into account a lot of real time information that we don’t have, like message traffic and signal strength. It’s not something that we as humans can follow very easily, but it definitely makes sense, and it’s quite an efficient system. Also remember that signal travels in 360° And depending on message traffic, for example, sometimes the quickest route is up and then over.
As long as you aren’t seeing problems, you don’t need to worry about the routing. If you are having problems, of course that’s a different issue, but it’s not usually the routing algorithms. It may be the number or placement of repeaters, of course. 
I have used those too, and also smart recepticles, but they didn’t have the range (600’) I needed. The Aeotec works great for a period, then drops off line.
I agree with @Awestun assessment of Aeotec Range Extenders. I’ve got three of them in a drawer somewhere. They never actually worked correctly.
i think i have 4 or 5 put away. what i did find out a while back was that the aeotec battery backup sirens make GREAT repeaters. things in the same room link to them and the sirens are more likely to link to each other from room to room.