Apple Catalina Appears to Introduce Massive Jitter

Mark Tinka mark.tinka at seacom.com
Thu Oct 29 16:39:08 UTC 2020



On 10/29/20 18:05, Blake Hudson wrote:

> On the latest Catalina 10.15.7 from a MacBook Air (early 2014) via 
> WiFi to Google Wifi Mesh router (only a single unit network):
>
> Over 2.4Ghz through 3 interior walls:
> --- 192.168.86.1 ping statistics ---
> 100 packets transmitted, 100 packets received, 0.0% packet loss
> round-trip min/avg/max/stddev = 1.440/15.078/213.538/30.541 ms
>
> Over 5Ghz through 1 door:
> --- 192.168.86.1 ping statistics ---
> 100 packets transmitted, 100 packets received, 0.0% packet loss
> round-trip min/avg/max/stddev = 1.557/24.614/137.233/39.015 ms

This is what I'm talking about. Why would you have such massive jitter 
on wi-fi to your local router?

You're hitting 213ms on 2.4GHz and 137ms on 5GHz. This doesn't seem odd 
to you?

Never had this issue pre-Catalina (I understand it may have been 
introduced in Mojave, but I came from High Sierra).


> This is a real world test with several iPhones, 2.4GHz WiFi only 
> cameras, and an iPad being used for zoom (remote school) while running 
> these tests.

Same for me. There are tons of devices on my WLAN, and only the one 
running Catalina behaves this way.

No drama for the rest.


> If you were not aware, on a Mac you can hold the Option key while 
> clicking on the WiFi icon to see more options as well as more 
> information about your current WiFi connection, including the realtime 
> Tx rate, channel, and when your Mac is searching for new networks 
> (mine does this every few seconds, it seems).

Yes, I am aware about the on-board macOS wi-fi diagnostics, and the good 
ol' trusted "airport -s". But those aren't enough.

I ended up spending money on NetSpot to see what's going on. Nothing 
there either. All I can tell is that Catalina is the problem; how 
exactly, is not yet very clear.


> From an experience perspective, all applications seem to work fine for 
> us. Including uploading to YouTube (a regular event as my spouse is a 
> teacher) and Zoom/Teams/FaceTime/your teleconference app of choice 
> (used by all of us).

So even though apps like Zoom report mild packet loss while on wi-fi 
(0.1% - 0.10%), it's not a train smash.

In general, everything works fine. But it doesn't feel 100%.

For the Youtube upload, I've found it to be temperamental, but I'm 
making it work for the time being.

Mark.



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