Visitor
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4 Messages
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,
Responses
user_a45315
Visitor
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4 Messages
1 m ago
Our internet has continued to drop 3 or 4 times today….
3
0
EG
Expert
•
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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