Question

One peer is connected via wifi and one via ethernet to lan port. The ping between the two peers is usually low (single ms) but spikes up to be high (several hundred ms) on a very periodic pattern. The same pattern appears from the wifi peer to any other source on the internet. I have here three graphs, graphing a ping to google.com, cloudflare.com and a local peer. I also have the same graph (except the peer is reached via a VPN) where I am connected to a mobile hotspot to my phone. Seems like something fishy is happening on the RUT240 network. What's up?

Answer 1

Hello,

Perhaps the RUT240 is positioned in a polluted RF environment? Appliances like microwaves could greatly impact the signal noise, which would result in higher ping times. Without changing some variables it will be quite hard to determine the cause. Could you try placing the WiFi client close to the RUT240?
Also, how much throughput could be expected at once from the wireless client? Perhaps these ping times increase during a period of high data transfer speeds?

Best regards,
DaumantasG

Comments

Hello, high data transfer speeds seems not to be the case, as I can max out my download link and have the pattern be identical. I can also install stuff, creating a CPU load, and get the same pattern. I see the same pattern sitting right next to the antenna. I am in a large warehouse/garage at the moment, I can see six wifi networks (very low amount imo) on my list. It's mostly nothing here. And the spikes are VERY periodic, and they appear on much longer timescales than the pictures allude to.

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Just to clarify, none of these factors seems to be affecting the device, correct?

It's quite hard to say what could be causing these issues, but I would be leaving toward the environment. Of course, hardware failure should also not be ruled out. One way this could be checked is if the spikes are long enough (>5min), the RUT240 could be rebooted, and after it boots up, check if the ping still has a big delay.

Have you tried a different wireless device to check if this is device specific or is always happening in the RUT240?

Also, make sure you are on the latest firmware.

  

Best regards,
DaumantasG

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Hello,

Correct, none of these factors affect the device. The issues shows up over long periods of time, easily longer than 5 minutes, and persists inbetween reboot. 

I can isolate it to the RUT240's wireless network. Let me present my case. I have three devices, A which is on RUT240 wifi, B which is on RUT240 ethernet, and C which is on another wifi elsewhere.

A <-> B does have periodic ping spikes as in the OP

A <-> C does have periodic spikes

B <-> C does not have periodic spikes

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Could you try manually changing the WiFi channels of the RUT240 to check if the issue is present in all of them?

This can be done by navigating to Network → Wireless → click the pencil icon on the global WiFi settings. Change the channel from Auto to the lowest, if the issue reappears, change to the highest.

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Changing wifi channels seems to have done it. Thanks for the advice.