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Forum Discussion
Spanning Tree problem with Orbi RBR50
I have been having network problems with my Orbi system for a few months now.. The symptoms are similar to issues others have reported, where satellites and other devices gradually disappear from then network. I have upgraded (and downgraded) the firmware multiple times, done many 'factory resets' and the problem still persisted.
I have finally worked out what is going on... and it's either a bug in the Orbi firmware (currently using V2.5.1.16), or in an Aukey USB-C docking station.
The symptoms are as follows:
I bought an AUKEY CB-C71 USB-C Hub (https://shop.aukey.com/products/8-ini-1-usb-c-hub-with-100w-pd) to use as a 'docking station' for my laptop ... i.e. a power supply is connected to the hub, and the hub is connected to the wired ethernet via the RJ45 jack and a monitor. I can then plug the whole thing into my macbook air's USB-C port with a single cable.
This all works fine, but when I "undock" the laptop to use it elsewhere, the ethernet port on the hub *stays enabled*. This means that:
a) the ethernet lights on the hub are blinking the whole time, but even worse
b) one by one all the other devices on my wired network get disconnected.
I don't understand why the media autodetect is not working properly and shutting down the link (I imagine this is an issue with the hub).
But ... the other wired devices on my ethernet getting dropped seems like it is probably something to do with 'spanning tree' topology discovery https://en.wikipedia.org/wiki/Spanning_Tree_Protocol. This is most likely an issue with the RBR50 firmware.
My home network has several switches. The RBR50 is plugged into the 'root' switch (a TP-link) and all the other switches and devices are connected to other ports on this switch. The USB-C hub is plugged directly into one of the RJ45 ports on the RBR50.
(normally there would also be an RBS50 satellite connected to the root switch, using wired backhaul, but I have shutdown&removed the satellite completely while debugging this problem)
I'm wondering what the best way is to fix/avoid this problem? It would be extremely tedious to have to disconnect the RJ45 cable from my router every time I unplug the laptop. Are there any diagnostics that can be turned on to understand why the RBR50 is shutting down the rest of my wired network? Are there any config options that might affect this behavior?
35 Replies
have you tried plugging the hub into one of the switches to see if it makes an impact?
And the problem doesn't happen at all if the hub hasn't been plugged in?
Another thing you can do is simplify it to make sure its the hub.
just run the router, the hub, and 1 device. disconnect everything else temporarily. run it for the period of time that it usually takes. See if it stays stable or if there's any other issues.
I've found the more complex you make a network, the more challenging it is to troubleshoot.
plemans wrote:have you tried plugging the hub into one of the switches to see if it makes an impact?
I only discovered this late last night so my wife and I are currently enjoying having a stable network for a little while! I'll certainly try that experiment when it's not likely to cause an outage (and outrage).
plemans wrote:And the problem doesn't happen at all if the hub hasn't been plugged in?
Correct ... I have no problems if I leave that hub disconnected or powered off. (I have even brought up the RBS50 on the wired backhaul and it appears 100% stable.)
Even more conclusively, when all the devices on the wired network have gone away, I can unplug that port of the RBR50 and after a little while the wired devices start reappearing. I left the network in a broken state last night, but unplugged the USB-C hub (on a whim) and by morning everything had come back.
I suspect that what's happening is that the rogue port is somehow 'reflecting' packets it receives and making the router think that various MAC addresses on the wired network are downstream of that port - STP decides there is a loop and starts turning off other parts of the network. With the port disconnected, STP timeouts fire and it eventaully rediscovers the topology.
plemans wrote:I've found the more complex you make a network, the more challenging it is to troubleshoot.
Too right... (and I have a PhD in computer science)
It's also kinda hard to debug problems like this when all the instructions are on the internet! ;-)
pbarham wrote:
plemans wrote:have you tried plugging the hub into one of the switches to see if it makes an impact?
Just in case other people reading this get the wrong idea, I should probably make it clear that the 'hub' we're referring to isn't an ethernet hub, but a USB-C hub that happens to have a builtin 1Gbe ethernet adapter.
It really shouldn't have the RJ45 port enabled when the usb isn't connected to a host, but it's a powered USB hub and the lights come on as soon as you attach power. The packet activity light on the hub's RJ45 port was blinking even without an attached laptop.
The root cause might be that when a laptop is disconnected, the ethernet adaptor is left running (I've opened a support ticket with Aukey).
But... I don't fully understand why that should have a knock-on effect on the rest of my wired network.
You're right that I should probably try an experiment plugging the USB-hub into one of the other switches on my network- but they are all in different rooms (the cable moderm and Orbi router are the only things in my home office - so using it as a handy ethernet switch seemed convenient!)
I'll look around and see if I have a spared ethernet switch in my networking parts bin and see if the problem requires direct connection to the RBR50. (note- I mainly posted here because so many other people appear to have 'disappearing devices' problems and the firmware revision notes for V2.5.1.16 explicitly mention fixing this)
I observe the same behavior on my orbi with a "FLYLAND USB C Hub". If there is nothing connected to it but a ethernet cable is plugged in, everything goes haywire after a few minutes and wired devices can no longer be pinged. Not the entire network shuts down but large parts of it. All wirelessly connected devices continue to be happy.
In my case I have the offending device plugged directly into a sattelite which itself is also on ethernet backhaul. I have not tried what happens if there is another switch in between.
This USB hub has a ethernet port?
mitsuhiko wrote:I observe the same behavior on my orbi with a "FLYLAND USB C Hub". If there is nothing connected to it but a ethernet cable is plugged in, everything goes haywire after a few minutes and wired devices can no longer be pinged. Not the entire network shuts down but large parts of it. All wirelessly connected devices continue to be happy.
In my case I have the offending device plugged directly into a sattelite which itself is also on ethernet backhaul. I have not tried what happens if there is another switch in between.
pbarham wrote:This all works fine, but when I "undock" the laptop to use it elsewhere, the ethernet port on the hub *stays enabled*. This means that:a) the ethernet lights on the hub are blinking the whole time, but even worseb) one by one all the other devices on my wired network get disconnected.Can you elaborate on what you mean by the other devices on the network get disconnected? Do they lose network connectivity and/or does your laptop lose access to them? Does it affect both wireless and wired devices?
It is a bad thing that one device in your home can cause other devices to become disconnected. Even if it's a problem caused by your USB-C hub misbehaving in someway, the Orbi should not allow this to upset the rest of your network.
Mikey94025 wrote:
pbarham wrote:This all works fine, but when I "undock" the laptop to use it elsewhere, the ethernet port on the hub *stays enabled*. This means that:a) the ethernet lights on the hub are blinking the whole time, but even worseb) one by one all the other devices on my wired network get disconnected.Can you elaborate on what you mean by the other devices on the network get disconnected? Do they lose network connectivity and/or does your laptop lose access to them? Does it affect both wireless and wired devices?
All the wired devices in the router's 'attached devices' list disappear. They typically go away in groups, 2 or 3 at a time (but this is maybe because of the slow page refresh). Not sure if the groups are related to being on the same ethernet switches. The whole process usually takes just a few minutes before all the wired devices are gone (from the router's perspective).
Once they 'disappear', the devices are no longer pingable by numeric IP address, although this is admittedly from a laptop that's on the wireless network (The laptop still has internet connectivity when all this is happening and can access the router's stats web pages). When I go and physically look at the affected devices, their ethernet ports appear to have 'signal' in that the LEDs are lit. But no packets (at least, the tx/rx lights don't seem to blink IIRC).
I don't know off hand whether the wired devices still have connectivity (between themselves, or to the internet), since they are mainly things like NAS, printers or 'smart device' bridges. I guess I should probably put another laptop on the wired part of the network and see if *it* can ping the NAS (It probably won't be able to access the internet via the router if the router doesn't believe it exists!). From the non-blinking LEDs I'm guessing not, but haven't verified.
Does the Orbi system work correctly wiht out this USB 3.0 dock device connected?
Seems like this is a device issue rather then a Orbi issue.
I along with others don't have this device however do have Orbi connected with switches and have not seen any STP problems in a long while. Some problems with STP came from managed switches which had IGMP protocols enabled when used in between the RBR and RBS. The fix for this is to disable IGMP protocols on managed switches.
