A

Visitor

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6 Messages

Tuesday, March 8th, 2022 11:08 PM

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Intermittent internet outages

Hello,

I've been experiencing intermittent internet outages since I've had Xfinity Internet (Blast) installed at my home. The outages happen multiple times per day, and can last for up to 10 minutes or so. There is no connection to the internet at all while it's happening.

To troubleshoot this myself I've replaced the included Xfinity router/modem device with my own, as well replaced the ethernet cable with a brand new one. In all setups I've been testing I've been seeing this issue happen on both Wi-Fi (2.5GHz and 5GHz) as well as hard wired via ethernet cable. No matter what hardware I replace the issue persists.

I've also had an appointment where a technician came out to my house. He arrived when the internet was down and ended up replacing the splitter in the box located outside of the house. The internet came back up when he tested it and he left, but then the internet went out again a few hours after he left.

I have run out of things to try, and the fact that the issue persists after swapping out so much hardware makes me think this cannot be an issue on my end. If anyone has anything they could suggest I would appreciate it.

Thank you

Accepted Solution

Visitor

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6 Messages

3 years ago

I'm writing this update to mark it as the "accepted answer" in case anyone else has this same issue and finds this thread.

The issue for me was too much noise on the line causing the disconnects, and to attempt to fix it myself I've replaced every piece of hardware inside the house meaning that the issue existed outside of the house either at the box or the telephone pole.

On Saturday the 12th (2 days ago) the tech came out and I went over everything I had done. There were no splitters on the coaxial cable coming into the house, the modem had been replaced, and the ethernet cable had been replaced as well and tested by plugging it directly into the modem, bypassing the router. He agreed it had to be coming from outside of the house and checked the box, then checked the cable coming from the telephone pole. He either replaced or re-crimped the cable, and I think he replaced the ground wire coming from the box outside as well (I wasn't standing over his shoulder), and after that he tested it and found a good signal inside the house. He mentioned that the connection at the telephone pole was corroded and he replaced it, and he was confident that it would fix my issue.

I haven't had a disconnect in the 2 days since then when prior to this it was happening multiple times a day, and visiting the modem webpage (192.168.100.1 for me) shows no error logs except for the ones prior to the tech visit.

To summarize, the fix for me was to schedule a technician appointment and have the tech check the telephone pole connection. If you've tested or replaced all of the hardware in your house then that might be what you have to do as well.

(edited)

Expert

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110.1K Messages

3 years ago

What do the modem's signal stats look like ? Try getting them here; http://192.168.100.1 or here http://10.0.0.1 

Please copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.


What is the exact make and model number of the modem / gateway device ?

Visitor

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6 Messages

3 years ago

Thanks for the reply! The modem is a Netgear CM500, and the router is a Netgear Nighthawk R7000.

I've pasted the requested info below:

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 8 351000000 Hz 7.8 dBmV 43.4 dB 37005 62917
2 Locked QAM256 9 357000000 Hz 7.9 dBmV 43.5 dB 36216 65777
3 Locked QAM256 10 363000000 Hz 7.9 dBmV 43.4 dB 35948 63205
4 Locked QAM256 11 369000000 Hz 8.1 dBmV 43.5 dB 31976 57572
5 Locked QAM256 12 375000000 Hz 8.2 dBmV 43.7 dB 30307 59424
6 Locked QAM256 13 381000000 Hz 8.3 dBmV 43.7 dB 29099 59799
7 Locked QAM256 14 387000000 Hz 8.3 dBmV 43.7 dB 28780 55991
8 Locked QAM256 15 393000000 Hz 8.3 dBmV 43.8 dB 28432 55969
9 Locked QAM256 16 399000000 Hz 8.3 dBmV 43.7 dB 27832 56410
10 Locked QAM256 17 405000000 Hz 8.3 dBmV 43.8 dB 26227 56154
11 Locked QAM256 18 411000000 Hz 8.3 dBmV 43.7 dB 27060 53084
12 Locked QAM256 19 417000000 Hz 8.1 dBmV 43.4 dB 26250 55242
13 Locked QAM256 20 423000000 Hz 8.2 dBmV 43.4 dB 24686 55038
14 Locked QAM256 21 429000000 Hz 8.2 dBmV 43.4 dB 24873 52703
15 Locked QAM256 22 435000000 Hz 8.4 dBmV 43.4 dB 24120 53359
16 Locked QAM256 23 441000000 Hz 8.6 dBmV 43.5 dB 23516 54081
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 4 5120 Ksym/sec 35600000 Hz 42.8 dBmV
2 Locked ATDMA 5 5120 Ksym/sec 29200000 Hz 43.3 dBmV
3 Locked ATDMA 6 5120 Ksym/sec 22800000 Hz 43.9 dBmV
4 Locked ATDMA 7 5120 Ksym/sec 16400000 Hz 43.8 dBmV

Expert

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110.1K Messages

3 years ago

Are there any modem RF error log entries being shown ? If so, please post them as well in their entirety (copy and paste them, don't post a screenshot) but redact the CM MAC and the CMTS MAC addresses for your privacy. They are considered to be personal information. Personally identifying information is a violation of their forum guidelines. The forum bot will not allow your post to be seen publically.

Visitor

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6 Messages

3 years ago

I've pasted the log with all personal information redacted below:

Time Priority Description
2022-3-9, 12:29:48 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:27:06 Warning (5) Dynamic Range Window violation
2022-3-9, 12:26:48 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:22:12 Warning (5) Dynamic Range Window violation
2022-3-9, 12:22:06 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:21:00 Warning (5) Dynamic Range Window violation
2022-3-9, 12:20:54 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:16:59 Warning (5) Dynamic Range Window violation
2022-3-9, 12:16:53 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:13:47 Warning (5) Dynamic Range Window violation
2022-3-9, 12:13:41 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:12:09 Warning (5) Dynamic Range Window violation
2022-3-9, 12:12:05 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:09:47 Warning (5) Dynamic Range Window violation
2022-3-9, 12:09:41 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:09:41 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:09:41 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:09:30 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:09:30 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:09:30 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:09:23 Warning (5) Dynamic Range Window violation
2022-3-9, 12:09:06 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:59 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:35 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:34 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:33 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:32 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:32 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:31 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:31 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:30 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:30 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:29 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:29 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:28 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:27 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:26 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:26 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;
2022-3-9, 12:08:25 Warning (5) Dynamic Range Window violation
2022-3-9, 12:08:25 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.0;

Some additional info: I've had 2 techs come out so far. The first was when the Xfinity service was first set up, and the tech installed the box outside with the splitter/coax as well as a 10db Attenuator between the coaxial line and the Xfinity Arris modem. The second tech visit was after I replaced the xfinity device with my own netgear devices, and the tech came out and swapped the splitter and removed the attenuator from the coaxial line. I still have the attenuator here and I've tested the connection with it on and off, but the random disconnects still happen. At the time of copying the error log above I've removed the attenuator as that is how the technician left it. In my experience adding the attenuator reduces the frequency of the disconnects but does not eliminate them entirely. I will add the attenuator and post that log in another comment in case it contains different information.

Thanks for your help so far

Official Employee

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2.5K Messages

Hello @AdamEWF! Our team can help.

Can you direct message us your name and address, please? Make sure you are signed in with your Xfinity credentials.

  1. In the top right corner, you'll see a little chat icon near the bell icon. Click the direct message icon
  2. Click the "New message" (pencil and paper) icon
  3. In the 'To' line, type "Xfinity Support" there. A drop-down list appears. Select "Xfinity Support" from that list (an "Xfinity Support" graphic replaces the "To:" line)
  4. Type your message in the text area near the bottom of the window
  5. Press Enter to send it. An official employee, such as myself or whoever is first available, will respond. Thanks!
I am an Official Xfinity Employee.
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Was your question answered? Please, mark a reply as the Accepted Answer.tick
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Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
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Expert

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110.1K Messages

3 years ago

O/k so even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on. Perhaps there is noise ingress into the line(s) / an upstream channel / return path impairment 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 (Cable Modem Termination System) to check for any real-time degradation and / or error reports, see your node / cable plant, and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !

Visitor

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6 Messages

3 years ago

I got the reply and sent support a message, thanks for your help EG I really appreciate it!

Official Employee

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2.5K Messages

Hey Adam! Thank you for reaching out to us in our subreddit. My review of your account shows that you definitely have some issues with the Upstream transmit Power and receive power. I'd like to ask you some questions to narrow down the solution to this issue. I may need to send some signals to your device which will take you offline for up to 10 minutes. Would now be a good time to do this? If I can't fix this remotely, I will get you scheduled with one of our expert technicians. To start have you removed your router and tested the connection directly from your modem? This would be to eliminate the router as an issue. 

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Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
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Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
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Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

Expert

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110.1K Messages

@AdamEWF​ My pleasure !

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We ask that you post publicly so people with similar questions may benefit from the conversation.

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Expert

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110.1K Messages

@XfinityThomasC​ wrote; "Thank you for reaching out to us in our subreddit."

FWIW, these are the Help Forums, not reddit.

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I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
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I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
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I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Visitor

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6 Messages

@XfinityThomasC​ Yes I've tried it with just the modem connected to my PC via ethernet cable, the same issue still occurs. You can send signals at any time, I am ready.

Visitor

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3 Messages

@XfinityThomasC@AdamEWF Can either of you help me with my issue with intermittent connection...I drop like every 10 minutes and I would love the assist......

I am using Comcast's Modem - Model: CGA4131COM Vendor:Technicolor and it intermittently hangs ever 5 minutes.  I have even had Comcast techs come out at least 6x.  I don't understand why the modem keeps dropping connection and I have had it changed out 4x.  Help!

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