AT&T Fiber: Slow Internet (Latency / Packet Loss) started on or right after 6/30

Which of those DNS servers you plotted to do you use as your Primary and Secondary DNS servers?  Is the Cloudflare one of them?

It looks like you are near Atlanta, given your id, and because I did a tracert to 32.142.143.102, which went through 12.242.113.21 the hop before.  I am 150 miles from Atlanta and most of my traffic goes through there. I don't see anything amiss at the moment with that hop.  A quick survey of some destinations shows that little of my traffic takes that route... not even Cloudflare CDN traffic, except for that headed for the Cloudflare DNS.

I used to see ping tests to the Cloudflare DNS jump by 10-20 ms for an hour or so before dropping back to the normal ~11 ms, but that hasn't happened in over a month (so my records tell me).  And it typically happened while I was asleep, so I didn't notice until I saw the log.

I  use Cloudflare for DNS on 1.1.1.1 and 1.0.0.1 for DNS.  Yes, I'm near Atlanta.  My neighbor has the same service and has also reported having issues.  

I appreciate you doing some testing as well.  The service is still pretty bad compared to the way it's been for the last several years.  I don't know where I go from here.  We went from easily streaming 4k video across the house with zero issues to constantly buffering video if someone else was watching 4k video.  Note all my TVs / set-top boxes are wired cat 6e on 1GB switch.  Also having issues with services like discord with 400ms latency normally around 20.

Working my job and connecting to AWS Console UI stalling out. Connecting to dominos.com stalling and had to reload several times.  Using the Amazon app on my phone while connected to wifi is slow, and products are slow to load.  Amazon Prime Video on computers and set-top boxes have blank boxes while images load in the background.

Everything was instant.  Not I honestly feel like my t-mobile hotspot is more consistent than my home network.  

I've taken my router out of the mix and I have a new gateway and the tech says my fiber connection "looked good".

I don't use Cloudflare for DNS I use 1.1.1.1 and 1.0.0.1 for DNS.  

Perhaps you are unaware that the owner of 1.1.1.1 (and 1.0.0.1) is Cloudflare, so you are, in fact, using Cloudflare DNS if you're using 1.1.1.1.  And traffic issues to your DNS server can be debilitating for web browsing.

We went from easily streaming 4k video across the house with zero issues to constantly buffering video if someone else was watching 4k video.

Even a 300 Mbps connection shouldn't have an issue with two 4K streamers.  I was about to point a finger at local Wi-Fi until you said that you used Ethernet.  It's hard to believe that either AT&T, its peering partners, or your video source would be affected by an second 25 Mbps stream.  It's hard to tell without some rigorously partitioned testing where the issue actually lies.

Sorry @JefferMC Yes.  I meant to say I was using Cloudflare. I tried switching to 8.8.8.8 and 8.8.4.4.   I'm not using WiFi for any of my testing the computers, and TVs, and set-top boxes I've referenced are all wired 1GB.

Yeah I agree it's hard to think that AT&T fiber would have an issue handling the types of traffic I typically handle.

I'm going to install iperf in AWS tonight in a few regions and run some tests locally and see what kind of results I get over TCP and UDP.  

I'm pretty sure it's external to my network as I've not had any issues with local network internally.  As previously stated I've tried wiring to the back of the BGW320-505 gateway too and haven't seen any drastic difference in performance.

I've been meaning to put wire in my UDM-Pro, if I have time I'll try putting that in place to do some A/B testing as well as doing a VLAN from the back of the BGW320-505 to specific places in the house to see if it has any notable differences.

Thanks again for the dialog @JefferMC 

@ATTHelp I have taken my 3rd party router out of the mix.  Also as stated my neighbor down the street started having the issue at the same time and I asked again today if he's still having the issue and he does.  So I'm pretty sure this is external to my house and maybe subdivision specific.

Thanks for the update on your service, @adac-solutions.

To further assist you with this issue, we'll need to speak privately via DM.

Please be on the lookout for a message from us at the top right corner of the screen. You should see a red dot on the chat icon next to the bell icon. We look forward to assisting you!

Jarod, AT&T Community Specialist

@adac-solutions there have been occasional issues where a group of people in a geographic area (LA; Madison, WI; Florida) have issues with periodic increased latency and low bandwidth.  I remember 3 or 4 cases just over the past year.  This could be another instance of that.  

If we can get several more people to report the issue, it may help get AT&T to devote a network engineer to investigate it.

Thanks @JefferMC .  I shared the link to this post with my neighbor, but he hasn't chimed in yet.

That being said @ATTHelp .  Elves must have been making little shoes last night, because everything is back to normal this morning.  I confirmed with my neighbor and his is also working now.

So magically as our internet went to crap, it's back to working good again.  I'm continuing to collect metrics for the next few days, but all graphs are green with no issues including the one that was showing an issue for Cloudflare DNS 1.1.1.1.

And we're back to slow and even gone internet now.

As day after posting that the internet was great all of the problems popped up again.  Considering I've made zero changes since my last two posts from my end I'm not sure how it would be anything but the AT&T network between my AT&T Gateway and the internet.

This morning in fact I was without internet for a few hours starting at 12:30am EDT to just before 3am EDT (7/11/2022).

And if the graph isn't enough my night owl teens both texted me around 1am saying the internet is completely out.  Also, my smarthome hub notified me via push notification to my phone that connectivity was lost at roughly the same window.