U

Visitor

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13 Messages

Sat, Nov 27, 2021 9:34 AM

Internet connection drops several times a day. This happens almost everyday!

Hello. I have been dealing with this issue for a while now and finally ran out of patience, so I called and they sent a tech out. The tech was unable to find anything wrong with wiring. My router was very behind in firmware updates, so we were hopeful that updates would solve the issue, it didnt. He said if that didnt fix it, then to plug into my modem directly. I did that and it still didnt fix it. I was thinking I have had this equipment for a while now (5-6 years) so I went and bought a new modem today and plugged my PC into that. The problem still persists! I was planning on calling again tomorrow, but came across this forum and wanted to see if I could get some recommendations since I've seen lots of people get help here! I logged into my modem and have a screenshot of my Downstream Bonded Channels since I saw this is what people were posting. Any help is much appreciated! Thank you for your time!

EG

Expert

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91.5K Messages

2 m ago

The stats that you posted so far a good / in spec. You need to also post the upstream power level figures and the error log entries, 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.

What is the exact make and model number of the new modem ?

(edited)

Visitor

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13 Messages

@EG Thanks for responding! I really appreciate you! Here is the upstream bonded channels. I'm not exactly sure how to find the error log entries. The only things I see other than the Upstream and Downstream are OFDM for both. Is that what you are looking for? The modem is a Netgear CM1000 DOCSIS3.1!

Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 1 16400000 Hz 48.0 dBmV
2 Locked ATDMA 2 22800000 Hz 48.3 dBmV
3 Locked ATDMA 3 29200000 Hz 48.3 dBmV
4 Locked ATDMA 4 35600000 Hz 47.3 dBmV
5 Locked ATDMA 5 40400000 Hz 48.8 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV

(edited)

EG

Expert

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91.5K Messages

2 m ago

From the manual;

 To view and clear the event logs:
1. Launch a web browser from a computer that is attached with an Ethernet cable to the 
cable modem or from a computer that is connected to a WiFi router that is attached with an 
Ethernet cable to the cable modem.
2. Enter http://192.168.100.1.
A login window opens.
3. Enter the cable modem user name and password.
The user name is admin. The default password is password. The user name and 
password are case-sensitive.
The BASIC Home page displays.
4. Select ADVANCED > Administration > Event Log.

Visitor

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13 Messages

@EG I somehow missed that! Thanks! Here is the log! I hope I posted it correctly!

2021-11-26, 19:13:45 Notice (6) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Critical (3) No Ranging Response received - T3 time-out;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2021-11-26, 19:12:38 Critical (3) Resetting the cable modem due to docsDevResetNow
Time Not Established Critical (3) No Ranging Response received - T3 time-out;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2021-11-26, 12:25:21 Critical (3) Resetting the cable modem due to docsDevResetNow
Time Not Established Critical (3) No Ranging Response received - T3 time-out;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2021-11-26, 12:17:15 Critical (3) No Ranging Response received - T3 time-out;
2021-11-26, 12:17:10 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;
Time Not Established Critical (3) No Ranging Response received - T3 time-out;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
Time Not Established Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2021-06-04, 02:03:14 Critical (3) Telnet user logged out.
EG

Expert

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91.5K Messages

2 m ago

O/k let's try some troubleshooting stuff before I escalate this to Comcast employees.

The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

Visitor

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13 Messages

@EG I dont see any unneeded coax cable splitters. The coax cable in the house is in good condition too. Everything is fitted well and there is no corrosion seen.

EG

Expert

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91.5K Messages

@user_dd9042 

O/k the error log entries indicate 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 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 !

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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13 Messages

@EG thanks again for all of your help and time. I really appreciate you!

EG

Expert

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91.5K Messages

@user_dd9042 

My pleasure ! It's why I lurk !!

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
XfinityEthan

Official Employee

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668 Messages

Hey, @user_dd9042. Thanks for working on this. It can be tough when everything looks good and needs a deeper dig.I checked everything out and the evidence points to an area issue impacting upstream. The UP snr is fluctuating to borderline and is slightly out of spec to most accounts. Upstream power is good. What I can do is keep an eye on it and check back with you. I did see there were other issue before today that point more towards your premise, but those are now gone and if they come back I will let you know. 

 

@EG Thanks.

I am an Official Xfinity Employee.
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

EG

Expert

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91.5K Messages

2 m ago

@user_dd9042 

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.

Sometimes it takes multiple home tech visits before one of them finally escalates it. Just sayin'. Good luck !


Good luck !

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