user_a45315's profile

Visitor

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4 Messages

Tue, Jun 22, 2021 12:10 AM

Internet is Continuously Dropping

Hi there,

I've been having an issue for the last week with our internet dropping several times a day, giving me a connection refused error.

So far I have checked the coaxial connection, and make sure that they're tight, and actually replaced the cable yesterday with no luck. 

Looking at my modem's information, I'm seeing a lot of T3 and T4 errors the since last Wednesday, and now getting a SYNC Timing Synchronization failure error.

My modem is a Motorola 24x8 Cable Modem, Model MB7621.

Time   Priority   Description 
 Wed Jun 16 06:44:47 2021    Critical (3)   Resetting the cable modem due to docsDevResetNow 
 Time Not Established   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0; 
 Wed Jun 16 06:44:13 2021    Critical (3)   Resetting the cable modem due to docsDevResetNow 
 Time Not Established   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0; 
 Fri Jun 18 17:51:18 2021    Critical (3)   Resetting the cable modem due to docsDevResetNow 
 Time Not Established   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0; 
 Sat Jun 19 09:53:38 2021    Critical (3)   Resetting the cable modem due to docsDevResetNow 
 Time Not Established   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.0;CM-VER=3.0; 
 Sun Jun 20 13:09:33 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:10:34 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:10:34 2021    Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:10:55 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:10:55 2021    Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:11:15 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:11:15 2021    Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:11:35 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:11:35 2021    Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:11:55 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:11:55 2021    Critical (3)   Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.0; 
 Sun Jun 20 13:11:57 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; 
 Sun Jun 20 13:14:44 2021    Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; 
 Time Not Established   Notice (6)   Honoring MDD; IP provisioning mode = IPv6 
     

The times listed in the error log above don't seem to correspond with with my actual internet is down, not sure if that's relevant? Our internet has gone down several times today for about 10+ minutes each time, but I'm not seeing these listed?

Downstream numbers:

Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
1 Locked QAM256 13 495.0 1.4 37.7 0 0
2 Locked QAM256 21 549.0 2.1 37.5 14 0
3 Locked QAM256 22 555.0 2.2 37.4 27 0
4 Locked QAM256 23 561.0 2.4 37.4 46 0
5 Locked QAM256 24 567.0 2.5 37.4 47 0
6 Locked QAM256 1 411.0 -0.1 37.4 528 654
7 Locked QAM256 2 417.0 0.0 37.5 498 651
8 Locked QAM256 3 423.0 0.2 37.6 377 345
9 Locked QAM256 4 435.0 0.9 37.8 336 129
10 Locked QAM256 5 447.0 1.1 37.7 231 90
11 Locked QAM256 6 453.0 1.1 37.7 212 34
12 Locked QAM256 7 459.0 1.1 37.6 125 0
13 Locked QAM256 8 465.0 1.4 37.7 67 0
14 Locked QAM256 9 471.0 1.6 37.8 63 0
15 Locked QAM256 10 477.0 1.5 37.8 16 0
16 Locked QAM256 11 483.0 1.4 37.8 20 0
17 Locked QAM256 12 489.0 1.2 38.2 48 24
18 Locked QAM256 14 507.0 1.4 38.2 22 0
19 Locked QAM256 15 513.0 1.3 38.1 13 0
20 Locked QAM256 16 519.0 1.3 35.8 29 0
21 Locked QAM256 17 525.0 1.5 37.9 7 0
22 Locked QAM256 18 531.0 1.8 37.6 3 0
23 Locked QAM256 19 537.0 2.0 37.9 8 0
24 Locked QAM256 20 543.0 1.8 37.9 11 0
Total             2748 1927

Upstream:

  Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
1 Locked ATDMA 4 5120 35.6 43.9
2 Locked ATDMA 1 5120 16.4 45.9
3 Locked ATDMA 2 5120 22.8 45.4
4 Locked ATDMA 3 5120 29.2 45.4
5 Locked ATDMA 5 2560 40.4 43.9
6 Not Locked Unknown 0 0 0 0.0
7 Not Locked Unknown 0 0 0 0.0
8 Not Locked Unknown 0 0 0

0.0

Would anyone happen to know what would be causing this?

Thank you,

This post was escalated on June 22, 2021 by EG

Responses

Visitor

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4 Messages

1 m ago

Our internet has continued to drop 3 or 4 times today….

EG

Expert

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88K Messages

1 m ago

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) /  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 !

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