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Internet connection constantly dropping

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Frequent Visitor

Internet connection constantly dropping

I have been having an issue with my internet connection dropping multiple times per day for a couple of months. After seeing that my old modem/router is obsolete, I purchased a new Nighthawk. It kept happening.

I called Comcast and they said there was a connection issue between the box on my street and my house, so they came out and replaced the cable. Didnt help.

I called back and the very nice rep suggested I replace all of my cords between the walls and my modem. Did that and it didnt help.

Next person I spoke with said I might have an internal wiring issue (my wiring was R6) and suggested I call an Electrician to potentially replace my wiring. I did that and he suggested I tap directly into the new line vs routing through my house wiring to see if that would be an effective fix. Did that and it didnt help, so he didn't think it was the internal wiring (so he is turning down business).

Next person I called said she could see the T3 timeouts and that I needed to have a technician come out. He came out and was ABSOLUTELY POSITIVE it was my house wiring because I kept the old wiring hooked up and it was interfering with the signal. HE WAS ABSOLUTELY POSITIVE IF I REPLACED MY WIRING THE ISSUE WOULD BE CORRECTED. Well, $400 later, it's still happening.

My Zoom calls are dropping and my if I can't run conference calls from home, my job could be in jeopardy.

Now, Comcast is telling me they won't help me (because my internet works most of the time) and someone will call me back in 48 hours. I have replaced every single wire and cable between the street and my modem. I've plugged my computer directly into the modem and it doesnt help. I've reset the modem more times than I can count. Doesn't help. I've unhooked the cables from my Xfinity boxes and only hooked up to the modem. Doesn't help.

The internet drops probably 10-25 times per day, for a few seconds at a time. Otherwise, it works absolutely perfect with download speeds consistently between 60 and 120 (we have 100).

Can anyone help me troubleshoot this issue?
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Frequent Visitor

Re: Internet connection constantly dropping

Time
Priority
Description
2020-4-28, 19:04:14
Notice (6)
WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2020-4-28, 19:04:13
Notice (6)
WiFi Interface [wl1] set to Channel 161 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2020-4-28, 19:04:10
Notice (6)
WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:7) - Reason:GUI
2020-4-28, 18:42:45
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 18:37:18
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 18:37:18
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 17:59:22
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 17:59:22
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 17:26:26
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 17:26:26
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 17:11:45
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 15:08:12
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 15:07:57
Critical (3)
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 15:07:56
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 15:07:51
Critical (3)
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 14:53:09
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 14:53:09
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 14:01:26
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:29:13
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:29:08
Critical (3)
SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:28:45
Critical (3)
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:28:43
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:28:43
Critical (3)
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:28:42
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:28:38
Critical (3)
SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:25:17
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:25:17
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:19:50
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:19:49
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:04:31
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 13:04:31
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 12:57:44
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
2020-4-28, 12:57:44
Warning (5)
MDD message timeout;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:49
Notice (6)
Honoring MDD; IP provisioning mode = IPv6
1970-1-1, 00:00:44
Critical (3)
No Ranging Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:40
Notice (6)
WiFi Interface [wl1] set to Channel 153 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:40
Notice (6)
WiFi Interface [wl0] set to Channel 6 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:37
Critical (3)
SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-4-28, 12:11:40
Critical (3)
Resetting the cable modem due to docsDevResetNow
2020-4-28, 12:07:18
Critical (3)
Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:8c:f2:50;CMTS-MAC=00:01:5c:6f:76:51;CM-QOS=1.1;CM-VER=3.0;
Highlighted
Expert

Re: Internet connection constantly dropping

What do the modem's signal stats look like ? 

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

Is this with a WiFi connection ? If so, for a test, does a computer hardwired directly to the router / gateway device with an ethernet cable have the same problem ?



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Frequent Visitor

Re: Internet connection constantly dropping

Connecting directly to modem via ethernet cord does not fix the issue.

I posted some stats above (after contacting Netgear) but am not technically savvy and could use some assistance in getting you the information you need. Thanks in advance for your help.
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Expert

Re: Internet connection constantly dropping

Those are error log entries. I need to see the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.




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Frequent Visitor

Re: Internet connection constantly dropping

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 9 603000000 Hz -0.5 dBmV 42.8 dB 0 0
2 Locked QAM256 30 507000000 Hz -1.9 dBmV 40.7 dB 0 0
3 Locked QAM256 31 513000000 Hz -1.1 dBmV 42.5 dB 0 0
4 Locked QAM256 32 519000000 Hz -0.6 dBmV 42.9 dB 0 0
5 Locked QAM256 33 525000000 Hz -0.4 dBmV 43 dB 0 0
6 Locked QAM256 34 531000000 Hz -0.2 dBmV 43.1 dB 0 0
7 Locked QAM256 35 537000000 Hz -0.2 dBmV 43.1 dB 0 0
8 Locked QAM256 36 543000000 Hz -1.1 dBmV 40.4 dB 0 0
9 Locked QAM256 37 549000000 Hz -1.3 dBmV 42.3 dB 0 0
10 Locked QAM256 1 555000000 Hz -1.5 dBmV 42.4 dB 0 0
11 Locked QAM256 2 561000000 Hz -1.1 dBmV 41.8 dB 0 0
12 Locked QAM256 3 567000000 Hz -0.8 dBmV 43 dB 0 0
13 Locked QAM256 4 573000000 Hz -0.4 dBmV 43.2 dB 0 0
14 Locked QAM256 5 579000000 Hz 0 dBmV 43.5 dB 0 0
15 Locked QAM256 6 585000000 Hz -0.1 dBmV 43.2 dB 0 0
16 Locked QAM256 7 591000000 Hz -0.1 dBmV 43.2 dB 0 0
17 Locked QAM256 8 597000000 Hz -0.1 dBmV 43.1 dB 0 0
18 Locked QAM256 10 609000000 Hz -0.6 dBmV 43.2 dB 0 0
19 Locked QAM256 11 615000000 Hz -0.9 dBmV 42.6 dB 0 0
20 Locked QAM256 12 621000000 Hz -0.6 dBmV 43.1 dB 0 0
21 Locked QAM256 13 627000000 Hz -0.3 dBmV 43.2 dB 0 0
22 Locked QAM256 14 633000000 Hz -0.2 dBmV 43.2 dB 0 0
23 Locked QAM256 15 639000000 Hz -0.5 dBmV 43.2 dB 0 0
24 Locked QAM256 16 645000000 Hz -0.6 dBmV 43.2 dB 0 0

 

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 90 5120 Ksym/sec 30100000 Hz 44.5 dBmV
2 Locked ATDMA 89 5120 Ksym/sec 36500000 Hz 45 dBmV
3 Locked ATDMA 91 5120 Ksym/sec 23700000 Hz 44.3 dBmV
4 Locked ATDMA 92 5120 Ksym/sec 17300000 Hz 44 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV

 

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Frequent Visitor

Re: Internet connection constantly dropping

 
 

I tried to post the results as a picture, but it didn't work.  I will try to DM you the pictures.

 

 

 

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Expert

Re: Internet connection constantly dropping

The signal stats are o/k but the error log entries indicate that something is going on. Perhaps there is noise ingress into the line(s) somewhere.

 

There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.

 

I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They will be able to poll the CMTS to see whether or not everything is in the green zone, see your node / cable plant and modem health, and also see a history plot for the modem. You should get a reply here in your topic. Good luck !

 



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New Poster

Re: Internet connection constantly dropping

It looks the the cable modem was just reset before posting the numbers as the corrections were all zeros. However, the Cable modem stats look very good for both S/N and power. Much better than what I see on my modem but I do not see the drop.

 

Need to check your equipment side.

1) do you see the drop from the other equipment such as laptop, TV streaming or tablet?

2) How long the drop last? 

3) Does it restore automatically or do you need to reset the modem

4) Is the drop tied to the Zoom or downloading (streaming)?

5) What is the model of cable modem? 

6) Is the cable modem new when it was registered to Comcast service?

 

 

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Expert

Re: Internet connection constantly dropping

This matter is already escalated to the Comcast Corporate employees...



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Frequent Visitor

Re: Internet connection constantly dropping

Thanks to EG for the escalation (!!!!!!) and thank you for the questions... answers below:


1) do you see the drop from the other equipment such as laptop, TV streaming or tablet? Every device in the house drops at the same time. iPads, laptops, everything.

2) How long the drop last? Anywhere from 3 secs to 3 mins

3) Does it restore automatically or do you need to reset the modem. Restores automatically

4) Is the drop tied to the Zoom or downloading (streaming)?
No... not tied to any particular app... everything drops

5) What is the model of cable modem? Netgear Nighthawk cv70002

6) Is the cable modem new when it was registered to Comcast service? Yes... bought it a month or so ago
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Frequent Visitor

Re: Internet connection constantly dropping

EG... thanks for your help. I really appreciate it. Someone is coming by my house today at 5pm. I hope he can do more than just check my house and the new line from my house to the street.

I spoke with my closest neighbor who also has Xfinity (2 doors down). He is also having the same issue. He used to work for Comcast and said the issue is definitely from pedestal to pedestal or between the pedestal and the node (sp?). I asked him why he hasnt done anything about it and he replied that he didn't want to go through what I've gone through the past two weeks (but thanked me for my efforts to this point 🙂 ) when it's just an annoyance for him.

My only hope is for someone at Comcast to be willing to spend the time, energy and effort to diagnose the issue outside of our properties. I hope the technician that comes out today is able to do that. And I hope that my neighbor experiencing the exact same T-3 timeouts (with an Xfinity modem) will help get us there.
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Expert

Re: Internet connection constantly dropping


@CvilleChef wrote:

I spoke with my closest neighbor who also has Xfinity (2 doors down). He is also having the same issue. He used to work for Comcast and said the issue is definitely from pedestal to pedestal or between the pedestal and the node (sp?). I asked him why he hasnt done anything about it and he replied that he didn't want to go through what I've gone through the past two weeks (but thanked me for my efforts to this point 🙂 ) when it's just an annoyance for him.

That's too bad because the more people that complain, the more effective the response will be. Good luck with it ! Please post back with how it goes.



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Official Employee

Re: Internet connection constantly dropping

Hello, CvilleChef! I'm glad you reached out to us for help with your services. 

Many of us are working from home too and definitely understand how important it is to have a consistent and reliable connection. I'd love to take a closer look and help monitor the work going on to make sure we get this fixed.  Please send me a private message with your first and last name, as well as your service address so I can assist. 

 

 To send a private message, click my name "ComcastTambrey", then click "send a message".


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Frequent Visitor

Re: Internet connection constantly dropping

It's been 3 days since the Tech came out to our house and confirmed the issue is not within our property, but between the nodes or between the node and pedestal. However, we are still having the same issues. I don't think anyone from Comcast has been out on the neighborhood trying to fix the issue. How long will this take. Nothing has been fixed and no one can seem to provide an estimate on how long it will take to fix the issue.
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Frequent Visitor

Re: Internet connection constantly dropping

Issue is now fixed. Tech came out and recommended a speed and modem upgrade. Said my issues stemmed from too many devices for my plan (100mbs). Upgraded to Blast and rented newest modem from Xfinity and have had no issues at all in the 24 hours since Tech and Supervisor came out for service visit.
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Frequent Visitor

Re: Internet connection constantly dropping

I'd like to see the follow up to this in a week to see if they somehow set your account as a temporary priority(since you may have doubled your bill with a faster connection and new modem rental) to get full speed for a bit and it falls off again, or if it is a permanent fix.   Especially since the tech said it was not a problem stemming from your property but somehow upgrading equipment on your property fixed it.  And unless you have several people in your house streaming on a bunch of wi-fi connected devices all at once every other appliance in your house could have a connection and it should not have fazed your router.  So unless Xfinity hotspot is piggybacking off the router creating a public connection you can't set a password for and all of your neighbors in range are using that I don't see how 100Mbps is not enough.  None of that would explain all the dropped connections

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Contributor

Re: Internet connection constantly dropping

Agree.  Plan speed shouldn't be a factor in T3 timeouts.  Will be interested to see if the problem is actually fixed.  If it has abated, would seem to point more to a hardware issue 

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Frequent Visitor

Re: Internet connection constantly dropping

I have a very similar sounding problem:

 

I have the exact same issue as well here in Seattle. Techs have been out three times. Swapped modems. Changed all the cables and connectors. Checked connections up and down the street. Checked the upstream and downstream signals looked good. Last guy was here for 2 hours and seemed really competent but he had no clue what might be causing this.

 

Has anyone had a resolution?