Hello All

i have a home router (192.168.1.1) and 2 ubuntu boxes (192.168.1.135, HostA), (192.168.1.252, HostB)

When i ping from HostA(135) to HostB(252), the timings are consistent.
$ ping -c 10 192.168.1.252 (from 192.168.1.135)
rtt min/avg/max/mdev = 2.906/6.337/25.024/6.255 ms

When i ping from HostB(252) to HostA(135), the timings are highly variable.
$ ping -c 10 192.168.1.135 (from 192.168.1.252)
rtt min/avg/max/mdev = 4.195/1927.896/3961.778/1401.682 ms, pipe 4

i also pinged the machines from home router (192.168.1.1)
192.168.1.1 to Host A --> High variability
--- (HostA) 192.168.1.135 ping statistics ---
10 packets transmitted, 8 packets received, 20% packet loss
round-trip min/avg/max = 405.044/2463.074/4520.020 ms

192.168.1.1 to Host B --> Consistent
--- 192.168.1.252 ping statistics ---
10 packets transmitted, 10 packets received, 0% packet loss
round-trip min/avg/max = 1.820/2.804/6.582 ms


Machines details:
Host A (135) : intel-NUC (i7-11th Gen, 32GB RAM, Ubuntu 22.04.2 LTS)
Connected via Wi-Fi (5Ghz) to home router.
Host B (252) : lenovo-ideapad (i3-3rd Gen, 8GB RAM, Ubuntu 20.04.6 LTS)
Connected via Wi-Fi (2.4 Ghz) to home router.

Both hosts were rebooted fresh and both reading were taken multiple times.

Any pointers/suggestions will be highly appreciated.
thanks in advance
santhosh

Ping is kind of a bad tool to test timing I'd think. Use a upload and download of some file to see maybe.

Might look at arp -a to see if the reason for packets lost might be due to trying to find it. I'd think that in general when you have wild issues you have connection/connector/cable problems. Even things like nearby motors/lights.

Wifi is the worst I'd think. Get a wifi scanner on your computer or phone to see what all is on those frequencies.

Guess distance on 5G?

Could be an issue with a power setting or other advanced setting in router.

1 members found this post helpful.

@jefro
Thank you for your suggestions, which prompted me to try 2.4GHz wifi.

When the system was connected to 5GHz wireless, the following oops messages were generated.(Attached:lq-2023-04-14-13-38-21.png)
And the ssh was very sluggish.. (scp gave 1.6MB/s for 457MB file )

Tried switching to 2.4GHz wireless. Now the ssh is not sluggish, scp gave 2.5MB/s for 457MB file
The kernel oops messages dont apprear.

And the ping times are better/somewhat consistent.

$ ping -c 10 192.168.1.135 (from 192.168.1.252)
--- 192.168.1.135 ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9012ms
rtt min/avg/max/mdev = 3.363/42.095/161.836/49.865 ms

192.168.1.1 to Host A --> much better.
--- 192.168.1.135 ping statistics ---
10 packets transmitted, 10 packets received, 0% packet loss
round-trip min/avg/max = 2.841/21.471/85.200 ms


Machines details:
Host A (135) : intel-NUC (i7-11th Gen, 32GB RAM, Ubuntu 22.04.2 LTS)
Now Connected via Wi-Fi (2.4Ghz) to home router.
Host B (252) : lenovo-ideapad (i3-3rd Gen, 8GB RAM, Ubuntu 20.04.6 LTS)
Connected via Wi-Fi (2.4 Ghz) to home router.

The connection between the kernel oops msgs and the network latency... yet to sort out.
https://sleeplessbeastie.eu/2022/04/...terrupt-storm/


thanks and regards
santhosh

Attached Thumbnails

 

nic driver?

@jefro

$ lspci
00:14.3 Network controller: Intel Corporation Wi-Fi 6 AX201 (rev 20)

$ lshw -class network

driver=iwlwifi driverversion=5.19.0-38-generic firmware=72.daa05125


Frankly speaking, i am not very sure of the reason why the ssh sluggishness (and ping latency reduced), after switching fromm 5GHz to 2.4GHz.
Also the connection between interrupt storm (

$ cat /proc/interrupts (snd_hda_intel is shown as the reason for kernel oops)
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
16: 0 176118 0 0 582742 0 0 0 IR-IO-APIC 16-fasteoi snd_hda_intel:card0

its a weird correlation..

thank you for the follow-ups

best regards
santhosh

iwconfig might be of some use to tell power / quality?