AC3100 randomly partially or fully stops routing traffic periodically

[Morac]

I bought my AC3100 in 2016 and for the most part it still works fine, but I’ve been having 2 problems that occur from time to time:

1. The router will just stop responding to all traffic over LAN and WAN and the Wi-Fi “disappears”. Effectively the router appears locked up though the lights flash on the front as it sees network traffic even if it never responds to it. At this point the only option is to power cycle the router. There is never anything in the logs indicating what went wrong. The logs just stop. This can happen every few days to every few months. I feel it is triggered by certain network devices. For example I see it happen much more frequently when I have a Shark robot vacuum on my Wi-Fi than without. The problem predates me owning a Shark vacuum though.

2. The second issue is the router stops routing some, but not all LAN network traffic. The first symptom of this is usually issues with Apple HomeKit where some devices appear offline even though they still appear to be connected to the Internet. I can verify there’s a problem by trying to do a network scan of devices on my LAN. Normally there’s around scanned 81 IP addresses (v4 and v6). When there’s a problem that drops to around 44. Outbound traffic to the WAN still works, but LAN traffic has issues. I can reboot the router from the UI to resolve this.

I’ve tried factoring resetting and setting up from scratch, but that never resolved either issue. Currently I’m running Merlin 386.9. I last had problems on Jan 14 (7 days ago) when the router locked up while uploading a lot of data.

First question, does anyone have any idea what’s wrong?

Second, do the newer ASUS routers run the same chipset (CPU/SOC) as the AC3100? I feel like the issues I’m having may be hardware related as my older Linksys router never had this problem. As such I’m trying to determine how likely I’d run into the same issue with a new ASUS router?

 

[wouterv]

Without knowing your exact setup or router configuartion, I suggest:

Guideline in case of unexplained router behavior:

1. If there are, disconnect all USB devices.
2. Install the latest available firmware version.
3. Reset to factory defaults.
4. Do not load an old configuration backup file.
5. Manual configure the router with the bare minimum, as:
   • Router Login Name.
   • Router Login Password.
   • WAN Connection Type, and what is required to connect to the Internet.
   • Wireless SSID's and WPA Pre-Shared Key's.
   • Leave everything else default.
6. Test the router behavior:
   1. Test with a wired connection first.
   2. Test with a wireless connection.
7. After the above works all well you can consider more manual router configuration changes.

Notes to the above guideline:

• Restoring a configuration backup might bring back old issues, that is why the manual configuration is advised.
• While making configuration changes: write them down so you do have a list of changes you made from factory defaults.
• Whenever you restore a configuration backup: only restore the backup to exactly the same firmware branch and version as it was made with.

Then, not sure what settings are in the AC3100, for a RT-AC68U I experienced those setting are best:

• Advanced Settings - Wireless - Professional - 2.4 GHz:
  • Modulation Scheme: Up to MCS 7 (802.11n)
  • Airtime Fairness: Disable
  • Explicit Beamforming: Disable
  • Universal Beamforming: Disable
• Advanced Settings - Wireless - Professional - 5 GHz:
  • Airtime Fairness: Disable
  • Universal Beamforming: Disable

 

[Morac]

As mentioned, I already did a factory reset and set up from scratch. There’s no real way to “test functionality” as everything works fine until it doesn’t. That can take days or months.

All the wireless settings recommendations are irrelevant as the problem impacts wired and wireless alike and wireless speeds are normally good.

 

[wouterv]

The robot vacuum cleaner uses Wi-Fi and you believe to see some relation to the problem, hence you get Wi-Fi related suggestions.
As long as you stay vague about your setup, the suggestions will be vague.
With 81 devices connected to you router, it might be that the router runs out of memory or into high CPU load.
Did you ever check the router CPU load and Memory usage?
Try a scheduled reboot of the router every day or every week.

To answer you second question: the RT-AC3100 is a rather old router, newer AX HND based routers perform much better.

 

[dogf]

Same for me, but with WDS, connections drops every 58sec.
AC3100 Merlin: WDS connection drop every 58 seconds | SmallNetBuilder Forums (snbforums.com)

 

[Morac]

I replaced my AC3100 with a GT-AX6000. I‘m hoping that doesn’t lock up.

 

[pplui]

i have a similar problem.
Connection is stable with just a few devices, but as soon as i start toi connect several tuya iot devices my ac3100 goes crazy. With my android phone sometimes i can not connect, sometimes i can connect but with no internet connection

Changed to my secondary ac68U (386.9) and everithing runs smoothly