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mag2023's profile

New Member

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30 Messages

Tuesday, February 21st, 2023 12:38 PM

DSL Service is Flapping

I've had the AT&T DSL service (25Mb/s tier) for several years.  It's been rock solid.  My significant other and I both work from home and have never been in danger of hitting the hard limits.  We previously had cable that promised some pretty substantial throughput (upwards of 10Gb/s) which sounds awesome, except for the fact that the service was shared by everyone in the community (partyline, essentially), and had a really bad track record of going out during the day, which meant 0 Mb/s, until they got around to fixing it.

We switched to AT&T ADSL Service at 25 Mb/s, which is dedicated and shared with no one.  The service has been reliable... until very recently.  One evening about a month ago, suddenly all of the services in the house stopped working.  No internet browsing, no streaming (television content), no making cell phone calls over WiFi (WiFi service (Edited per community guidelines), so using cell over WiFi)... to name a few.  After performing a bunch of diagnostics on the ARRIS device, my theory was that either the device was malfunctioning, or there was a hardware problem somewhere upstream.  I reached out to AT&T Cust Service.  The gentleman on the phone spent most of the call handling me, which I'm fine with if he is ultimately able to escalate to an engineer.  He spent an inordinate amount of time interrogating the device in my home (the ARRIS BGW210-700), I spent about an hour on the phone while he alleged to be running tests, he was making the case that the problem was between the ARRIS and my home network.  I explained repeatedly that I had already run the diagnostics on the ARRIS and that they clearly showed that the problem was upstream.  Here are some images of those diags:

Figure 1:  Running the internet speed test using the ARRIS-based utility complained because it couldn't contact the Test Server, and as a bonus, notice the massive latency, 8758ms:

 

Figure 2: After running the suite of ARRIS on-board diagnostics, the IP test failed, indicating a possible routing hardware issue:

Figure 3: Clicking into the details of the IP Test failure yields more insight into the problem, related to access to the Default Gateway (a problem upstream from my equipment):
Figure 4: Finally, a "PING" test to google.com which was coming back with 100% packet loss, in this case showed 50% packet loss plus the latency issue.
The customer service rep eventually agreed to change out my modem, which I installed two weeks ago.  The screen shots in this post were captured last evening, evidenced by the date/time stamps.  The new hardware didn't fix the problem.  
Would it be possible to speak with an AT&T engineer to figure out why this is happening.  This morning, as I write, all tests indicate everything is functioning properly, but I suspect that whatever caused the malaise yesterday afternoon (and a few weeks go) and lasted into the evening hours (flapping service) will likely happen again.  If there was a service outage due to routine maintenance, I was hoping to learn that from customer service, but customer service didn't share that when I called yesterday.
Are there any engineers on this forum?  I'm hoping this detail will help bypass the customer service support tier.

New Member

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30 Messages

7 months ago

UPDATE:  Friday evening.  

So, my service started flapping again.  Turns out that 1-foot flat cable was not the root cause.  This screenshot shows how the link started flapping again last evening just after 8pm.  

I reached out to the AT&T customer service.  I spoke with someone who said that they'd been with AT&T for 40 years and he knew exactly what needed to be done to fix it.  My curiosity was piqued.  When he explained what he was doing, I believe he said that he forced a new IP address assignment to my device.  The unit rebooted and when the broadband service came back online, I was getting perfect ping results.  He told me that he would check in with me on Monday (when his next shift was) and that if my service went down again, not to call in.  
[Saturday Update]
At about 9:30a this morning, the flapping began again.  I rebooted the broadband router to no avail, but the service seemed to stabilize after about an hour (about 10:30a), and it's been solid the entire day (as I monitor the stream of pings).
It would seem that the only way to determine the root cause would be for the technician to hook into the line while the service is flapping.

ACE - Guru

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9.9K Messages

7 months ago

And is your IP different?

New Member

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30 Messages

7 months ago

I can't answer that because I didn't take note of the IP address before he made the change.

ACE - Expert

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33.2K Messages

7 months ago

I suppose we should tell the people who can't get AT&T to change their Public IP that all they have to do is have intermittent communication issues and get the right technician and voila.

Have you come up with any idea as to the source of the large upstream usage?  Is it continuing?

New Member

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30 Messages

7 months ago

The down/up ratio has inverted.  Your theory about video usage seems the most plausible, we are both heavy users of Teams and Zoom during work hours.

New Member

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30 Messages

7 months ago

A casual observer might conclude by your comments that simply changing the IP on the public interface of the router is not a likely solution.

New Member

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34 Messages

7 months ago

Hey @mag2023 it sounds like you are in the same boat as a lot of us on this thread:

Broadband stays up but internet fails.

You check off a lot of boxes:

  • Working Uverse for years until late Jan or early Feb.
  • Since then random outages for random lengths of time
  • BGW210-700 router
  • AT&T tried to swap out hardware to no avail.

You can read my posts there but I'm pretty sure a router firmware update pushed out in late Jan or early Feb is causing this issue.  Mine started on 2/3  - it goes out when a lot of traffic starts to go out to the Internet.  It'll stop when whatever is pushing out the traffic finishes running. 

I don't have a solution and I'm not 100% sure I'm right (though I'm fairly confident) but if you can find what is causing the traffic surge when it goes down may get you back up quicker.  Maybe shutting one device down at a time until it comes back is the best place to start.   In my case it was an offsite backup running, it would always go down minutes after it started.  In another user's case it was when he started a file sync from OneDrive. 

Good luck and any updates or questions fire away...

(edited)

New Member

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30 Messages

7 months ago

Hey @gz1 ... thank you for the heads up.  I can head over to that thread and pile on.

New Member

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30 Messages

7 months ago

--- Mirroring my post in the other forum.

I was able to precipitate the service interruption (flapping) based on what the other forum thread called out.  I initiated an upload to OneDrive of a large file (Fedora Linux ISO).  As soon as the transfer began, the ping test began to wobble (flap)...

Furthermore, once the "flapping" was underway, I ran the Diagnostics and the IP Test failed...
So, my working assumption is that something on the ARRIS BGW210-700 (perhaps a firmware upgrade in late Jan 2023) may be causing the unit to malfunction when large upstream data transfers occur.  

ACE - Expert

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33.2K Messages

7 months ago

I don't really know how y'all avoided seeing this before now.  Is been this way for years.  Saturated upstream makes for a lousy connection.

Best fix is to limit upstream.  It may be necessary to acquire a third party router and put it between your network and the gateway. 

And, yes, it's pretty much impossible to actually get your IP address changed. If you had asked for that, he would have said 'no'.

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