Wifi problems: high packet loss, wifi disconnect

pure_bliss · 2021-04-22 09:42:42

Hello!

Problem

For some weeks I have been experiencing very high packet loss, and disconnects over wifi. The wifi access point is very close to my laptop, and should work fine. The problem came suddenly, without any hardware change, and things worked fine before.

Symptoms

The problem is most noticeable during online classes (video/sound drops out), and online games (usual high packet loss sypmtoms, I can describe it more if that would help). The packet drops / lags come in bursts, sometimes the connection is good for serveral minutes, then suddenly everything goes wrong. Even ssh sessions to other pc-s on the local network become unresponsive.

During these I noticed the following:

$ cat /proc/net/wireless
Inter-| sta-|   Quality        |   Discarded packets               | Missed | WE
 face | tus | link level noise |  nwid  crypt   frag  retry   misc | beacon | 22
wlp2s0: 0000   66.  -44.  -256        0      0      0    514     87        0

Discarded packets / retried packets count can go way out of hand (1k+).

Dmesg logs during this: https://bpa.st/26AA

A traceroute to one of the games server:

                              My traceroute  [v0.94]
----- (192.168.1.201) -> 74.91.113.100                    2021-04-07T21:12:10+0200
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                          Packets               Pings
 Host                                   Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. _gateway                            10.7%   159    1.7 1292.   0.9 7173. 1917.
 2. 145.236.238.158                      7.5%   159    3.4 1262.   2.7 7116. 1863.
 3. 81.183.3.38                          8.2%   159   35.6 1311.   3.0 7649. 1912.
 4. 81.183.3.38                          6.3%   159    3.3 1459.   2.8 8596. 2060.
 5. 81.183.3.54                          3.8%   159    3.5 1500.   2.8 8533. 2069.
 6. 80.157.204.37                        8.8%   159    9.4 1507.   8.2 8470. 1995.
 7. pd9ef3791.dip0.t-ipconnect.de        3.8%   159    8.5 1557.   8.3 8407. 2001.
 8. 80.156.163.254                       5.7%   159    9.9 1554.   7.8 8344. 1991.
 9. win-bb4-link.ip.twelve99.net         5.7%   159  170.8 1683. 170.1 8446. 1977.
10. ffm-bb2-link.ip.twelve99.net         3.8%   159  177.2 1640. 165.0 8392. 1946.
11. prs-bb2-link.ip.twelve99.net         2.5%   159  184.1 1539. 169.1 8318. 1914.
12. ldn-bb4-link.ip.twelve99.net         1.3%   159  177.3 1515. 165.2 8274. 1897.
13. nyk-bb3-link.ip.twelve99.net        46.8%   159  223.3 1242. 150.3 6920. 1708.
14. chi-b23-link.ip.twelve99.net         4.4%   159  177.9 1462. 170.7 8137. 1865.
15. telia-2.e10.router2.chicago.nfoserv  7.0%   158  173.1 1429. 164.3 8074. 1899.
16. v-74-91-113-100.unman-vds.premium-c  4.4%   158  134.7 1459. 132.4 7964. 1952.

$ uname -a
Linux laptop 5.10.32-1-lts #1 SMP Wed, 21 Apr 2021 12:28:13 +0000 x86_64 GNU/Linux

What I tried

The problem presists after I tried another wifi access point
Both 2.4GHz and 5GHz modes are affected
Everything works fine if I use cable for connection insead of wifi

Please tell me if any additonal logs are required, I'll post them. Currently I have no idea what causes this, and I'm looking for a way to figure out what this caused by.

Thanks!

belotroll · 2021-04-22 11:10:54

I recommend you try to use a wifi dongle to make sure the problem is not your built-in laptop wifi card.

progandy · 2021-04-22 11:27:41

For some weeks I have been experiencing very high packet loss, and disconnects over wifi. The wifi access point is very close to my laptop, and should work fine. The problem came suddenly, without any hardware change, and things worked fine before.

Maybe there was a change in the driver for you wifi device, you could try to use the lts kernel or downgrade to an older kernel package.

pure_bliss · 2021-04-22 11:39:42

progandy wrote:

For some weeks I have been experiencing very high packet loss, and disconnects over wifi. The wifi access point is very close to my laptop, and should work fine. The problem came suddenly, without any hardware change, and things worked fine before.
Maybe there was a change in the driver for you wifi device, you could try to use the lts kernel or downgrade to an older kernel package.

I am already using the LTS kernel. I don't know, if I can downgrade the wifi driver only. Since using linux I never ever had a problem with drivers But I'll try things out with the latest kernel.

belotroll wrote:

I recommend you try to use a wifi dongle to make sure the problem is not your built-in laptop wifi card.

That's one thing I wanted to try, but first I have to get one.

seth · 2021-04-22 12:13:27

Please post the complete system journal (sudo journalctl -b) after such episodes.
The dmesg excerpt shows you leaving the AP by local choice 30-80 seconds after being connected, might be https://wiki.archlinux.org/index.php/Ne … ets_(WiFi) in which case stopping NM and establishing a manual connection w/ wpa_supplicant & dhcpcd should™ remain stable, https://wiki.archlinux.org/index.php/Dh … supplicant

Alternatively you can try iwd insntead of NM, but will then have changed more than one element at once (ie. the cause remains somewhat unclear)

pure_bliss · 2021-04-22 17:37:39

seth wrote:

Please post the complete system journal (sudo journalctl -b) after such episodes.
The dmesg excerpt shows you leaving the AP by local choice 30-80 seconds after being connected, might be https://wiki.archlinux.org/index.php/Ne … ets_(WiFi) in which case stopping NM and establishing a manual connection w/ wpa_supplicant & dhcpcd should™ remain stable, https://wiki.archlinux.org/index.php/Dh … supplicant
Alternatively you can try iwd insntead of NM, but will then have changed more than one element at once (ie. the cause remains somewhat unclear)

The 'roamed from BSSID' entries are not present in the journal.

I'll try these, thanks. It will take some time to get another wifi adapter, and catch another one of these package drops, I'll update the post if I can find out anything.

seth · 2021-04-22 19:02:46

You can also post the journal - NM is usuallly very chatty.
Pay attention to signal strength changes and while the pattern doesn't really fit (though smells scanning related), https://wiki.archlinux.org/index.php/Ne … domization

pure_bliss · 2021-04-22 20:31:24

seth wrote:

You can also post the journal - NM is usuallly very chatty.
Pay attention to signal strength changes and while the pattern doesn't really fit (though smells scanning related), https://wiki.archlinux.org/index.php/Ne … domization

I will if I will be able to reproduce it. This morning I could barely use ssh on local network to my raspberry, but since noon there was only 13 dropped package till now. I can't think of anything that changed during.

seth · 2021-04-22 20:34:06

Radio noise?
Are there many SSIDs in sight?

pure_bliss · 2021-04-22 20:40:28

seth wrote:

Radio noise?
Are there many SSIDs in sight?

During laptop dealing with heavy packet losses I browsed reddit on my mobile phone (connected to same wifi, 2.4GHz), and didn't experience any problem. There are other access points in the apartment house (my neighbors), but only like 3-4. Wi-fi analyzer app on android shows that the access points channel I connect to does not overlap any other, and the AP and laptop are pretty close (5m max, nothing that should blocks signal)

pure_bliss · 2021-04-22 20:50:28

seth wrote:

You can also post the journal - NM is usuallly very chatty.
Pay attention to signal strength changes and while the pattern doesn't really fit (though smells scanning related), https://wiki.archlinux.org/index.php/Ne … domization

Ok, I have no idea why I didn't post the journal from today morning, I was so into looking forward to another one of these lags.

Here it is:
https://paste.ubuntu.com/p/MSgV3KgZnN/

edit: if you encounter messages saying that it couldn't request IP from a dhcp server, ignore it, I was messing with raspberry and pihole, and a dhcp server.

Last edited by pure_bliss (2021-04-22 20:51:38)

seth · 2021-04-23 08:21:07

The log goes from 08:43:08 to 09:31:34 and there're only two disconnects
1. at 08:44:39 because "user-requested" during the startup of NM
2. at 09:31:18 because "connection-removed" while the system shuts down.

At 08:57:20 there's a beacon loss, you're then failing to connect to ItsAlwaysTea and at 08:57:49 connect w/ ItsAlwaysTea-5G
At this point your IP changes from 192.168.1.100 to 192.168.1.201 and you seem to desperately try to mount a cifs (your pw shows up in the journal…) before your shutdown.
=> Is your problem about that?

pure_bliss · 2021-04-23 10:07:26

seth wrote:

The log goes from 08:43:08 to 09:31:34 and there're only two disconnects
1. at 08:44:39 because "user-requested" during the startup of NM
2. at 09:31:18 because "connection-removed" while the system shuts down.
At 08:57:20 there's a beacon loss, you're then failing to connect to ItsAlwaysTea and at 08:57:49 connect w/ ItsAlwaysTea-5G
At this point your IP changes from 192.168.1.100 to 192.168.1.201 and you seem to desperately try to mount a cifs (your pw shows up in the journal…) before your shutdown.
=> Is your problem about that?

During the logged interval I was setting up a raspberry with samba and dhcp / pihole, so the ip change is kinda normal. There weren't any disconnects that time iirc, only severe packet drops. Don't know if it logs that

Well yea, i know that I shouldn't pass pw by command line, but the server is only local, and its a dummy pw I dont use anywhere else, so no worries

pure_bliss · 2021-04-23 10:18:25

I have the journal entries from the day I had many disconnects during online class, but thats 2.5 MB. Couldn't find any paste-bin services that handle that big of a file (yet)

edit: But what about these?

ápr 23 12:21:05 laptop wpa_supplicant[464]: wlp2s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-71 noise=9999 txrate=175500
ápr 23 12:21:23 laptop wpa_supplicant[464]: wlp2s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-56 noise=9999 txrate=433300
ápr 23 12:22:05 laptop wpa_supplicant[464]: wlp2s0: CTRL-EVENT-SIGNAL-CHANGE above=0 signal=-59 noise=9999 txrate=117000
ápr 23 12:22:13 laptop wpa_supplicant[464]: wlp2s0: CTRL-EVENT-SIGNAL-CHANGE above=1 signal=-65 noise=9999 txrate=433300

Last edited by pure_bliss (2021-04-23 10:22:53)

seth · 2021-04-23 15:52:28

That's signal quality fluctuation - it's normal, but the signal is rather poor for "the AP and laptop are pretty close (5m max, nothing that should blocks signal)"
The package losses feed into that because weak signals will lead to damaged packages, causing them to be re-transfered.

Is the 2.4GHz connection more reliable?

You could either "split" (man split) the log or use eg. a google drive or wetransfer.

pure_bliss · 2021-04-23 17:04:12

seth wrote:

That's signal quality fluctuation - it's normal, but the signal is rather poor for "the AP and laptop are pretty close (5m max, nothing that should blocks signal)"
The package losses feed into that because weak signals will lead to damaged packages, causing them to be re-transfered.
Is the 2.4GHz connection more reliable?
You could either "split" (man split) the log or use eg. a google drive or wetransfer.

journal link

I think I once tried the 2.4GHz connection, and it wasn't good either, but I'll try it out again next time

seth · 2021-04-24 08:23:02

There're 4 beacon losses between 17:00 and 18:00 (half the time the SSID can't be found) and around 19:00 the nm-dispatcher service is constantly restarted.
I'd attribute the former to the less-than-great signal, any idea about the latter?

You should figure why the signal is to bad.
Do you use any power saving maanger (tlp etc)? Is it better on AC than on battery?

pacman -Qi linux-firmware

You could try passing this to the kernel, but that's grasping straws…

iwlwifi.power_save=false  iwlwifi.disable_11ac=true iwlwifi.disable_11ax=true

pure_bliss · 2021-04-25 08:24:32

seth wrote:

There're 4 beacon losses between 17:00 and 18:00 (half the time the SSID can't be found) and around 19:00 the nm-dispatcher service is constantly restarted.
I'd attribute the former to the less-than-great signal, any idea about the latter?
You should figure why the signal is to bad.
Do you use any power saving maanger (tlp etc)? Is it better on AC than on battery?
pacman -Qi linux-firmware
You could try passing this to the kernel, but that's grasping straws…
iwlwifi.power_save=false  iwlwifi.disable_11ac=true iwlwifi.disable_11ax=true

pacman -Qi linux-firmware

I'll try those kernel params, but as far as I know I don't have any power saving enabled. The laptop is constantly on AC.

If the signal would be bad, wouldn't it be constantly bad? The problems I described only happen occasionally, more noticeably when network usage is higher (online classes, online games)

I don't know about the 'nm-dispatcher' service, but I think it got restarted by KDE-s network settings, when I tried to fix things by enabling/disabling wifi. If I recall correctly I switched to cable at some point during the day the logs are from.

seth · 2021-04-25 15:40:07

more noticeably when network usage is higher (online classes, online games)

More packages, more retransmits if the signal is poor, more chance for timeouts.

The signal isn't good at all times - I get a similar signal across three rooms and two floors (mostly wood construction, I've been in -private- houses w/ bunker-grade reenforced concrete where the signal doesn't get out of the room ;-)
5m direct sight should™ yield a much better signal - does it get stronger if you move close to the AP?

pure_bliss · 2021-04-27 16:08:10

seth wrote:

more noticeably when network usage is higher (online classes, online games)
More packages, more retransmits if the signal is poor, more chance for timeouts.
The signal isn't good at all times - I get a similar signal across three rooms and two floors (mostly wood construction, I've been in -private- houses w/ bunker-grade reenforced concrete where the signal doesn't get out of the room ;-)
5m direct sight should™ yield a much better signal - does it get stronger if you move close to the AP?

I don't think that its the AP-s problem, I tried 2 AP-s, and booth had the same problems. I'll try to get an usb wifi stick, and try things with that. The only indicator of signal strength I know is KDE-s wifi icon, which shows the signal is pretty ok, only one bar is missing, which I think is because there is a couch in between (wooden, don't think that would cause random packet drops)

Also will try the things you mentioned. As I see there is no exact solution to my problem, and this must be some specific case, so I'll try to figure out something myself. Hoped that this was a simple issue, with an already existing solution, but now it seems like something, what requires lot of testing.

Just wanted to say that I'll try to solve this myself, maybe there is something I don't notice, and confuse you too, or need more time to understand something. But thanks for the help, I'm definitely trying what you suggested.

seth · 2021-04-27 21:05:39

iw dev wlp2s0 station dump

will print the signal and some more.
The idea is not that the AP might be at fault, but that something™ is impeding the signal, whether you can impact that by repositioning the antenna/notebook and whether that (hopefully stronger signal) has impact on the stability.

Arch Linux

#1 2021-04-22 09:42:42