High delays every 4 minutes on 2,4 GHz WLAN

Last week my son complained that he has problems when gaming. My investigation showed that sometimes the ping delays are extremely high. I installed Smokeping to monitor this a bit better:

I have a cascaded router setup.The IP that I am pinging is the broadband router connected to the Omnia so there is nothing else between my Raspberry Pi3 and the ping address. When zooming in it shows that the peaks are 4 minutes apart. What could this be? How can I narrow it down?

I have 3 WLANs configured, one on 5GHz and two on 2,4 GHz. This problem occurs on both 2,4 GHZ networks. The 5 GHz WLAN has occasionally a drop for 2 ms to 70 ms but not as regular and it does not have any packet loss. I am not sure when this started since for my own use those occasional delay are not as critical but I also noticed some sporadic delays in SSH sessions to my home server last week. I have a SSD installed so I had to move the WLAN cards. Other than this the Omnia is unchanged and I am not using the USB 3 ports.

for serious gaming, be a hero and work a cable to your son’s computer :slight_smile:

after you confirmd that this is really related to wifi, ofc, e.g by pinging throu your router by a cabled client or from the router itself

something like ping -fW.1 -w 300 to your broadband router

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So far my son has been content with his gaming experience. I am not sure yet how to get a cable there. Otherwise I would have done it already.

I have bridged the WLAN in question with some LAN interfaces. I also did connect a Raspberry with Smokeping to a LAN interface belonging to the same subnet:

Here this delay problem does not exist. The 5 GHz WLAN I tested from my laptop. Sometimes the delay went up from 2 MS to 70 ms but there were no dropped packets in 2700 pings.

So to me it seems that it really are the 2,4 GHz WLANs only that experience this problem.

Today my wife worked from home and had stability issues with the 2,4 GHz WLAN on her laptop. But I am not yet 100% sure that this is due to the above problem.

you could always pay someone to drill a few holes and install a cable-channel for probably less than what a new graphics card costs.
and like other major hardware upgrade, nobody would want to go back.
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could you test with another 2.4ghz ap that this is not some random wifi interference?

I did some more tests on the 2,4 GHz networks. The Omnia and two RPIs are in the same room. A Huawei LTE router is about 8 m away in another room (wooden walls).

One RPi is pinging the Huawei. The delays are consistently under 10 ms. At the same time the other RPi has the same problem as before pinging to my broadband router. So there does not seem to be any problem with interference. The only device really close to the Omnia is a managed HP switch. The RPi pinging the Huawei is also close to both of them. I might try tomorrow to move the HP Switch a little - just to make sure it does not create any interference.

I configured the RPi pinging via the Omnia WLAN to ping the network address of the Omnia (this network is only in this WLAN and not bridged with any LAN interfaces) and also to ping the broadband router which is one hop behind the Omnia. While both graphs show the same problem, the delay to the Broadband router is still noticeably higher:

Omnia:

Cisco