Ping latency spikes on Mac OS with Orbi -- what could be causing this?

[ralphch]

I just installed the Orbi, and I'm experiencing a very strange issue with ping latency from two Macbooks running Mac OS Sierra / High Sierra. When I ping the Orbi router or satellite station, I start seeing ping spikes every few seconds. It goes from a normal of ~3 to ~4ms, to upwards of 100ms. I'm standing right in front of each unit and connected to the 5 Ghz band.

I don't see this issue when I ping the Orbi from my iPhone. It will occassionally go up to ~15ms, but I'm attributing this is expected interference. There are a lot of APs around my apartment (upwards of 50).

Somewhat unscientifically, it seems that I can reproduce the latency spikes on my Macbooks when I click on the Wifi menu icon, which forces the Mac to scan for networks. This leads me to believe that the computer is constantly scanning for networks, which it might be a bug within Mac OS itself...

I have tried removing/adding the wifi connection, resetting PRAM and SMC, booting into safe mode, disabling the wifi icon in the menu entirely, turning bluetooth off, turning airdrop off, setting custom MTU, etc, all to no avail.

At this point, I would like to identify if the issue is with the Orbi or the Macs themselves.

Has anyone else experienced a similar issue? And do you have any ideas on how to go about troubleshooting further / fixing this?

Thanks!

[st_shaw]

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@ralphch wrote:

Somewhat unscientifically, it seems that I can reproduce the latency spikes on my Macbooks when I click on the Wifi menu icon, which forces the Mac to scan for networks. This leads me to believe that the computer is constantly scanning for networks, which it might be a bug within Mac OS itself...

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Clicking on the WiFi menu icon, or running any sort of WiFi scanning software, will cause periodic ping spikes as well as periodic slowdowns in throughput.  It's not an issue with Orbi and it's not a bug in OSX.  It's a side effect of the scanning software taking over your WiFi adapter periodically.

[ralphch]

@st_shaw thanks for your reply. This makes sense. However, I'm seeing the spikes even when not engaging with the Wifi menu, which leads me to believe that either (a) Mac OS is periodically scanning for networks in the background, or (b) there is something else causing the slowdown.

Earlier today I performed these tests at a friend's house that has Google Wifi and was able to verify that all Mac computers experienced the same issue, but one Windows computer did not. Simply pinging the access point results in spiking latency on every Mac, even when not engaging with the wifi menu -- though the latter does make it more pronounced.

So these results theoretically rule out any issues with the Orbit itself.

Do you know if there's a way to prevent Mac OS from scanning for wifi networks entirely?

[st_shaw]

I just tested my MacBook Pro on a Ubiquiti Unifi WiFi setup and it spikes up to around 100 ms about every 15 seconds.  I'm pretty sure it didn't do that before.

Pinging from a wired server to a wireless camera on the same network doesn't show the spikes.

So, it looks like it might be an OSX issue. I have no idea what's causing it. Could be related to a recent OS update.