AX88U periodic disrupted connection

byeuji

New Around Here
I've had this router AX88U router for a couple years now with both stock firmware and Merlin on it.
I've been experiencing long-term (basically almost as long as I've had the router) intermittent disconnections.

For a long time, I thought it was Comcast, but after switching to a new fiber ISP, I saw the issue continue. I began analyzing ping floods between each part of the network (my PC to the router, from the router to the modem, from the router to the local google.com IP). This produced proof that the latency was being introduced between my PC and the router.

I tried this on multiple PCs at once, pinging the router locally -- and when the latency jumped, it jumped simultaneously for all three PCs (one of which was running Linux, and two of which were hardwired to the router). These latencies were anywhere between 15-800ms (again, between my PC and the router, where anything >1 is basically unacceptable). These dips occurred at all times of day. The outages appear to occur whether the firmware is stock or Merlin, so after testing that briefly on stock, I returned the router to Merlin for the extra tools. The latency also seemed more consistently low after a router reboot, so I scheduled a router reboot every morning.

I also looked at all the physical measurements of the router and noticed the temperatures were consistently over 75 C. From what I was able to find via google, this seems to be pretty normal for this router. However, in my experience, 80 C is pretty much the silicon upper threshold for processors, and it was occasionally dipping into that. So I bought an aftermarket fan that fits onto the router body, and since installing that the temperatures have dropped into the 45-55 C range pretty consistently now (holy crud they should install a fan on these things).

However, these modifications have not changed the behavior of the router. For about 10 weeks, I have continued to see the large latency spikes. However, starting this week, with no change in firmware, hardware, software, etc. that I'm aware of, the latency spikes have graduated to a full on disconnect.
My computer registers these periods as No-Internet, and then it quickly corrects itself.

I don't see how changing the firmware back to factory is going to help this issue. I assume if this issue is more widespread, others would have heard about it. I bought this very expensive router for its reputation, power and stability, but I've reached my breaking point.

Do I just have a dud? I don't really want to spend another $300 to find out they all have this issue.
 

L&LD

Part of the Furniture
Welcome to the forums @byeuji.

You may have a dud, but buying another one isn't required to determine if this is your specific router or not.

The following link and the suggestions within is where I would start to eliminate hardware issues (vs. software/misconfigurations).

Fully Reset Router and Network

After the router has been fully reset as per above, the best practices below should ensure that the stability continues.

Fully Reset / Best Practice Setup / More

The following may also be helpful too (particularly the Control Channel suggestions).

Almost all L&LD Links
 

Mike-48

Occasional Visitor
I've had this router AX88U router for a couple years now with both stock firmware and Merlin on it.
I've been experiencing long-term (basically almost as long as I've had the router) intermittent disconnections.

[...]

I don't see how changing the firmware back to factory is going to help this issue. I assume if this issue is more widespread, others would have heard about it. I bought this very expensive router for its reputation, power and stability, but I've reached my breaking point.

Do I just have a dud? I don't really want to spend another $300 to find out they all have this issue.

I wonder if you have the same problem that I do. I don't have your skills, so I don't know whether it's related to additional latency or not. I'd be interested to hear if you ever solve the problem.
 

byeuji

New Around Here
I wonder if you have the same problem that I do. I don't have your skills, so I don't know whether it's related to additional latency or not. I'd be interested to hear if you ever solve the problem.

My disconnection is always extremely brief -- no more than a few seconds.

I bought another AX88U and replaced the original today (literally 5 minutes ago finished the restore), just to see if the issue re-occurs. I'm using the same config (as exported and imported from the prior router).

If the issue doesn't re-occur, I'll RMA the old AX88U and use the replacement as a mesh router. If it does re-occur, I'll probably return the new one and share my configs here as appropriate and see if folks can pick it apart.
 

L&LD

Part of the Furniture
The fact that you used a saved backup config file from another router (no less) is enough to know you'll find it flakey.

Perform the appropriate steps below, if you're really interested in properly testing the new hardware.

Do not use a saved backup config file, particularly from another router (even if its the same model). Do a minimal and manual configuration after you've flashed the firmware and then fully and properly reset the router to factory defaults.

[Wireless] ASUS router Hard Factory Reset | Official Support | ASUS Global

Fully Reset / Best Practice Setup / More
 

byeuji

New Around Here
Thanks L&LD, I'm aware that can be complicated, but I need to take small steps here because I was at wit's end and prepared to throw everything in the trash. I did a full 30-30-30 each step of the process in getting the router updated to the latest stock firmware, then flashing merlin, then loading JFFS with my certificates and vpn profiles, and then loading previous settings.

I can report that after 24 hours, the router appears stable with very little variation in ping latency and so far no packet loss recorded.

If I start running into problems, then doing a manual re-configuration with your linked reset process will be my next step.
 

L&LD

Part of the Furniture
Almost every step you list is wrong.

There is no 30-30-30 reset for Asus routers.

Importing a saved backup config file negates the reset which didn't happen in this case.

The fact that the network seems stable is not from due process, it is purely luck.

Be ready to do it right at the most inopportune time.
 

byeuji

New Around Here
I'm aware there's no 30-30-30 in your list. I still performed it because it's not a bad thing to do, and I'm used to it from DD-WRT. All it tells me is that the settings stuck despite unexpected power loss.

Please don't assume because I said I did one thing and not explicitly what you said to do means that I'm drawing some conclusion. I'm just doing what I know how, and seeing what result it produces.

For instance, if this is stable, I have good indications that the router import settings feature is working as one would expect. That doesn't mean I'm trusting it always will.
 

L&LD

Part of the Furniture
So being helpful is having bad manners now. :rolleyes:

Okay.
 

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