GL-AR300M: Long video conference breaks Wi-Fi

giner · 2020-06-26T18:59:51.357Z

Hi,

I’m using GL-AR300M in Router mode and experiencing the following issue: after a long video call (>= 1.5 hours) Wi-Fi becomes unstable. The longer call is the more unstable Wi-Fi becomes. Sometimes it comes to the point where authentication on Wi-Fi starts timing out.

There are a few things I noticed:

If I don’t make any video calls Wi-Fi works stably for days (downloading files form internet doesn’t seem to break it)
Restarting Wi-Fi from LuCi (https://192.168.8.1/cgi-bin/luci/admin/network/wireless) always helps. If Wi-Fi cannot authenticate anymore I have to connect using Ethernet cable to be able to restart Wi-Fi.
Trying to monitor traffic with tcpdump I noticed that when Wi-Fi is unstable network packets from Wi-Fi to laptop/mobile seem to go well, however packets from laptop/mobile rarely reach Wi-Fi device
Disabling WMM seem to help avoiding this problem however disabling it seems to limit Wi-Fi network bandwidth

Any suggestions?

Best regards,
Stanislav

giner · 2020-06-30T17:34:23.279Z

Upgraded to the latest version of OpenWRT (openwrt-19.07.3-ar71xx-generic-gl-ar300m-squashfs-sysupgrade.bin specifically). There is a feeling that overall network is faster and more stable however WiFi issues didn’t go anywhere. Here is how I can usually reproduce it:

Create a Google Meet session and connect with two devices (laptop and android in my case, video is enabled on both).
Wait for 20-40-60 minutes until WiFi hangs (no traffic moving anymore, no ability to connect to the access point).

Interestingly on the new firmware WiFi is not degrading slowly but stops working suddenly. Connecting through LAN and restarting WiFi from LuCI makes it work again. As I mentioned above disabling WMM helps to avoid the issue however this also makes the WiFi network a lot slower.

Any thoughts? How to debug? Is it hardware / driver / hostapd issue or something else?

giner · 2020-07-01T00:33:28.624Z

The symptoms seem to be similar to this issue #13681 (ar71xx: wr741nd wifi crash after some time) – OpenWrt

robotluo · 2020-07-01T01:48:12.659Z

When this happens, you can use the top command to see the CPU load.

giner · 2020-07-01T02:06:48.938Z

When this happens the CPU usage is low

robotluo · 2020-07-01T04:29:48.116Z

Give me some time and I will simulate the test.

giner · 2020-07-10T03:30:27.179Z

This issue is still happening regularly and I’m not sure what to do with that.

If it’s software issue - I’d report on openwrt and wait for updates. If it’s hardware issue - I’d buy another router. How to debug and know who’s fault it is?

Another issue is that I cannot find a way to detect this on the router itself. If the issue was detectable I’d configure a monitoring job to reboot it automatically.

Any suggestions?

giner · 2020-07-11T03:00:22.062Z

Have just installed the latest snapshot (OpenWrt SNAPSHOT r13770-edbc8e5512 / LuCI Master git-20.190.40190-44b0fcb) from here https://downloads.openwrt.org/snapshots/targets/ath79/nand/openwrt-ath79-nand-glinet_gl-ar300m-nor-squashfs-sysupgrade.bin. Will monitor for a while and see if this helps.

Kernel: Linux OpenWrt 5.4.50 #0 Fri Jul 10 09:39:05 2020 mips GNU/Linux
Based on ath79 (as opposed to ar71xx available on stable firmwares)

giner · 2020-07-14T00:33:21.180Z

@robotluo, I’m back with the results.

Switching to the latest snapshot version of openwrt based on ath9 fixed the issue with Wi-Fi. Wi-Fi is fast and stable now! This could be the end of story however WAN link turned out to be unstable this time. ETH1 interface keeps up and down frequently.
I dug a bit into the issue with WAN link and found that reverting a couple of commits from the master branch and rebuilding the image solves the issue with WAN too.

Result: Now my GL-AR300M works without any issues.

alzhao · 2020-07-16T10:41:00.324Z

Thanks for sharing. Yes observed that wifi was fixed recently.

Will upgrade to 1907 then.

giner · 2020-07-16T11:37:53.219Z

@alzhao, upgrading to 19.07.3 didn’t solve Wi-Fi issue for me. Only upgrading to the latest master did (which will become 20.x version at some point).

Firmware Version: OpenWrt SNAPSHOT r13835+2-8242c6de29 / LuCI Master git-20.192.49615-3dd289b

alzhao · 2020-07-16T12:52:26.793Z

I understood, upgrading to the latest tunk version.