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Google Wifi Bufferbloat Problem

Keegs
Community Member

When any device on the network (wired or wifi) is downloading or uploading the ping on my network skyrockets from 15 ms to 500+, frequently hitting 1500ms or timing out.

When running speed tests the ping to the router stays at 1ms, but pings to the modem skyrocket and sometimes time out.  This seems to be an obvious bufferbloat problem.

Connection Speeds: 450Mbps Down, 20Mbps Up

14 REPLIES 14

olavrb
Platinum Product Expert
Platinum Product Expert

There is built in QoS (fq_codel), but I've read that it stops interfering at some bandwidth threshold.

I escalated this thread in hopes of getting some official response on this.

Could be worth testing with "preferred activities":

And if you have a router in front of Nest Wifi that is not in bridge mode, meaning you run double NAT, that could be a problem here too.


I don't work for Google.

Keegs
Community Member

Thanks, I do have preferred activities enabled which is why I probably haven't noticed this problem in any video calls thankfully, really wish Google expanded it's QoS options.  To be kicked from an online game because someone is downloading or uploading a file is aggravating.  I do remember google wifi working fine with our previous internet plan that was around half the speeds we currently have, kinda insane that I'm seriously considering downgrading our internet to deal with bad QoS.

No second router here

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@olavrb, thanks for the help!

 

@Keegs, thanks for reaching out. I'm sorry to hear that you're having an issue with your Google Wifi. I'd love to know more about this and I have a few questions:

 

  • Are you experiencing this with a single service or across the entire network?
  • Has anything changed on your network since they started experiencing this issue?

Looking forward to your response.

 

Thanks,

Edward

Keegs
Community Member
  • This seems to affect all devices on the network, usually it's only noticeable if there's a significant load on the network.
  • I'm not certain when the problem began, I believe it was when we upgraded our internet speeds from around 200Mbps down to 450Mbps down when I noticed while downloading files on my PC that the responsiveness of webpages was significantly slower, but I chalked it up to QoS slowing my connection, or a problem with my PC.  It wasn't until recently I noticed this happens when any device is using lots of bandwidth that pings will skyrocket.  No other significant changes to the network besides upgrading our internet that I can think of.

 

dtaht
Community Member

Two notes - 1) Once you pass a certain speed, the bloat shifts to the wifi. Which can be quite horrendous. I don't know if nests's wifi has the fixes we put into linux 4.18 and later for the the mt76, ath9k and ath10k chips (relevant paper: https://www.cs.kau.se/tohojo/airtime-fairness/ )

2) When I last looked nest was effectively applying fq_codel and a shaper to the link at speeds below 300Mbit but ran out of cpu to do it above that. IF the bloat is actually coming from the ISPs link at your 400mbit, you can put a 500mbit+ capable router in front of that, keeping your nests for wifi, and your network will get overall better. You can test this by testing wired. I do not know if I can recommend products that are 500+ capable here, but everybody knows I'm a huge fan of openwrt on a decent x86 box, and there are multiple commercial offerings nowadays with sqm that can run at these faster rates, well.

 

It is odd, and depressing, that sometimes a "faster" link behaves so much worse than one with well managed queues on it.

EdwardT
Community Specialist
Community Specialist

Hi folks,

 

@dtaht, thanks for the help!

 

@Keegs, thanks for the response. What type of cable are you using from your ISP modem to your Google Wifi device? Also, could you try a 2 minute power cycle on your devices? Please try the following steps:

 

  • Disconnect the power from the modem.
  • Disconnect the Ethernet cable and power cord from the parent point.
  • Disconnect the power cord from the child point.
  • Leave everything unplugged for 2 minutes.
  • Start a timer to track.
  • Check the make and model of the modem and make sure there isn't a backup battery. If there’s a backup battery, let's remove the battery, otherwise it won't perform a power cycle.
  • Connect the power to the modem and allow the modem to fully power on before proceeding. This process can take up to a minute.
  • All light indicators should be solid colors.
  • Connect the Ethernet cable, then the power cable to the parent point. Wait until it’s fully back online.
  • Connect the power cord to the child point(s).

Thanks,

Edward

 

Jeff
Community Specialist
Community Specialist

Hi Keegs,

I just wanted to jump in real fast to see if you saw Edward's latest reply and to see if you still needed some help on this or if you were able to get it sorted out. If you are still needing some help, just let us know and we'll be happy to continue helping.

Thanks,
Jeff

Jeff
Community Specialist
Community Specialist

Hi everyone,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.

Thanks,
Jeff

Princesss
Community Specialist
Community Specialist

Hi there,

 

Due to inactivity, I'll go ahead and lock this thread in 24 hours. Feel free to start a new thread if you need assistance with your Google Wifi and we'd be glad to assist you further.
 

Best,

Princess

dtaht
Community Member

Just a note: I'm one of the original authors of fq_codel, cake, etc. I tried to point out over here, many moons ago:

https://www.reddit.com/r/GoogleWiFi/comments/qnnwpg/bufferbloat_on_google_wifi/

some flaws in the config dump I was able to analyze, notably the side-effects of GRO are a PITA.I passed those observations over to the original author of the arl + fq_codel code, but I have no idea if you took them up, or this product is configured similarly.

If y'all could find a way to share your config and observed problems with me, perhaps I can help optimize your product(s). But please pass those observations along to whoever might care.It's also generally been my hope that y'all would jump on cake as the per-host FQ is awesome (IMHO).

https://arxiv.org/abs/1804.07617

Also the wifi code has been in the kernel for a while and should scale much better than shaping does:

https://www.cs.kau.se/tohojo/airtime-fairness/

Hope this helps!

Jhonleanmel
Community Specialist
Community Specialist

Hey folks,

 

@Jeff and @EdwardT, thanks for the helpful responses.

@dtaht, we appreciate the help.

@Mussels, thanks for getting back to us and sorry for the delay.

 

Give these steps a try:

 

  1. Perform a 2-minute power cycle
  2. Check if cabling is secure.
  3. Attempt to use a different Ethernet cable, if possible.
  4. Reboot your affected device.

Keep us posted.

 

Thanks,

Mel

Hey there,

I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Thanks,
Mel

Mussels
Community Member

Just had this happen to me as well, after several years of never seeing this behaviour

While gaming and a different PC was updating, pings went from 25ms to 150ms, and stayed there until the downloads had finished

50Mb down 20Mb up

It is NOT POSSIBLE for me to bridge the modem/router so support have refused to help, despite DMZ for port forwards and IPv6 having everything function normally

If this continues i'll be ditching the google mesh, it's useless when they forcibly change settings for the worse and we can't roll them back or manually adjust them.

Mussels
Community Member

Oh i cant edit my post - forgot to state i'm WIRED as well, not wifi.

A device downloading off the wifi, caused me to lag when i'm directly wired to the gigabit WAN port of the AC2200 nest router.