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carl4638
1st Topic

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3 Messages

Tuesday, January 11th, 2022 5:19 PM

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Router keeps randomly rebooting

I have a Netgear C7000v2 and my internet keeps resetting on a daily basis, multiple times a day. On the router all the lights will go yellow then the router reboots and internet comes back after a few minutes, but it's very frustrating. I've tried replacing all the cables, reseating the cables, and I've done multiple manual reboots, but nothing resolves issue

I checked the logs and here is what I am seeing this

2022-1-11, 10:34:41 Notice (6) WiFi Interface [wl0] set to Channel 1 (Side-Band Channel:N/A) - Reason:INTERFERENCE
1970-1-1, 00:00:49 Notice (6) Honoring MDD; IP provisioning mode = IPv6
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 11 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:39 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
2022-1-10, 14:34:19 Critical (3) Resetting the cable modem due to docsDevResetNow

Here's the stream levels

Procedure Status Comment
Acquire Downstream Channel 525000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 21 525000000 Hz 5.9 dBmV 40.1 dB 0 0
2 Locked QAM256 42 651000000 Hz 5.5 dBmV 40.3 dB 164 110
3 Locked QAM256 43 657000000 Hz 5.8 dBmV 40.4 dB 125 104
4 Locked QAM256 44 663000000 Hz 6.2 dBmV 40.5 dB 97 106
5 Locked QAM256 25 549000000 Hz 5.2 dBmV 40.3 dB 0 0
6 Locked QAM256 26 555000000 Hz 5 dBmV 40.3 dB 0 0
7 Locked QAM256 27 561000000 Hz 5 dBmV 39.7 dB 0 0
8 Locked QAM256 28 567000000 Hz 5.2 dBmV 40.4 dB 0 0
9 Locked QAM256 29 573000000 Hz 5.3 dBmV 40.3 dB 0 0
10 Locked QAM256 30 579000000 Hz 5.3 dBmV 40.2 dB 0 0
11 Locked QAM256 31 585000000 Hz 5.3 dBmV 40.1 dB 0 0
12 Locked QAM256 32 591000000 Hz 5.3 dBmV 40 dB 0 0
13 Locked QAM256 33 597000000 Hz 5.1 dBmV 39.9 dB 16 0
14 Locked QAM256 34 603000000 Hz 4.9 dBmV 39.8 dB 20 0
15 Locked QAM256 35 609000000 Hz 4.9 dBmV 39.9 dB 40 0
16 Locked QAM256 36 615000000 Hz 4.8 dBmV 39.7 dB 40 1
17 Locked QAM256 37 621000000 Hz 3.8 dBmV 39.9 dB 0 0
18 Locked QAM256 38 627000000 Hz 3.6 dBmV 39.5 dB 0 0
19 Locked QAM256 39 633000000 Hz 3.7 dBmV 39.9 dB 0 0
20 Locked QAM256 40 639000000 Hz 3.9 dBmV 39.8 dB 0 0
21 Locked QAM256 41 645000000 Hz 4.1 dBmV 40.3 dB 0 0
22 Locked QAM256 22 531000000 Hz 4.8 dBmV 40.3 dB 0 0
23 Locked QAM256 23 537000000 Hz 4.8 dBmV 40.3 dB 0 0
24 Locked QAM256 24 543000000 Hz 4.6 dBmV 40.3 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 5 2560 Ksym/sec 40400000 Hz 42 dBmV
2 Locked ATDMA 1 5120 Ksym/sec 16400000 Hz 43.4 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 22800000 Hz 41.9 dBmV
4 Locked ATDMA 3 5120 Ksym/sec 29200000 Hz 41.8 dBmV
5 Locked ATDMA 4 5120 Ksym/sec 35600000 Hz 41.8 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

Question

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Updated 

3 years ago

2.6K

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user_bb801b

Contributor

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167 Messages

3 years ago

Is the issue happen on device connected via WIFI, Ethernet, or both?

 Thanks and good luck.

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EG

Expert

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110K Messages

3 years ago

Even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on (there is a loss of block sync entry). 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 can check the CMTS (Cable Modem Termination System) 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 !

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user_bb801b

Contributor

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167 Messages

3 years ago

Just my .2 cents but the technical stuff should be transparent to the user. Nice to see the logs but until tech puts meter to gateway and takes reading its all nice to know...

 That said, Im not seeing a response which may mean internet dropped completely or issue has resolved itself.

 Fingers crossed its the latter.


 Thanks and good luck.

2

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carl4638

Visitor

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3 Messages

@user_bb801b 

Issue has not been resolved. It was working alright today up until a few minutes ago, I pulled this from the Even Logs. MAC stuff cleared for privacy reasons

1970-1-1, 00:00:49 Notice (6) Honoring MDD; IP provisioning mode = IPv6
1970-1-1, 00:00:40 Notice (6) WiFi Interface [wl1] set to Channel 128 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:40 Notice (6) WiFi Interface [wl0] set to Channel 4 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:39 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC
1970-1-1, 00:00:37 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC
1970-1-1, 00:00:38 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC
1970-1-1, 00:00:39 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC

3 years ago

0

XfinitySara

Official Employee

 • 

1.6K Messages

Hey there, @carl4638! I'm sorry to hear that the modem is still having these reset issues. Thank you for bringing your concerns to the community! Our Expert was right, I'd like to look at your signal levels and see what we can do to resolve this for you. Could you please send our team a private message with your full name and full address? We can most definitely take a further look at this issue.

 

To send a "Peer to Peer" (private) message:
• Click "Sign In" if necessary
• Click the "Peer to Peer chat" icon
• Click the "New Message" (pencil and paper) icon
• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
• Type your message in the text area near the bottom of the window
• Press Enter to send it

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

3 years ago

0

EG

Expert

 • 

110K Messages

3 years ago

May I ask what part of the three items below does not indicate that their "internet does not drop completely" ?

"Router keeps randomly rebooting

I have a Netgear C7000v2 and my internet keeps resetting on a daily basis, multiple times a day. On the router all the lights will go yellow then the router reboots and internet comes back after a few minutes,"

 "the error log entries confirm that something is going on (there is a loss of block sync entry)".

Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;

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