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Frequent, but intermittent internet disconnects.
I have been enjoying my -new- Comcast-recommended Motorola MB8600 modem for >several weeks without issue<. It has suddenly started dropping its connection, which seems to be a very common theme. Indeed, I have checked and tightened connections. The events are random, and seemingly at the most inopportune moments - as I (like many) am working from home and conduct business over the various video and screen-sharing connections available. I have a very small, but "enterprise class" network - so changing service providers is a simple swap-out at the closet ahead of my firewall.
The modem dropped again this morning, so I restarted it, and then captured the information shown below.
Any help interpreting these logs would be appreciated.
Time | Priority | Description | |||
11:55:49 Fri Jun 12 2020 |
Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
11:56:02 Fri Jun 12 2020 |
Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
14:52:02 Mon Jun 15 2020 |
Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
14:52:03 Mon Jun 15 2020 |
Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
14:52:26 Mon Jun 15 2020 |
Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
14:52:36 Mon Jun 15 2020 |
Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
15:20:28 Mon Jun 15 2020 |
Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
15:20:29 Mon Jun 15 2020 |
Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
15:20:29 Mon Jun 15 2020 |
Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; | |||
Time Not Established | Notice (6) | Honoring MDD; IP provisioning mode = IPv6 | |||
06:47:09 Fri Jun 26 2020 |
Notice (6) | DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=00:40:36:61:71:03;CMTS-MAC=00:01:5c:7f:84:4b;CM-QOS=1.1;CM-VER=3.1; |
EG
Expert
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111.4K Messages
5 years 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) 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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XfinityJoeTru
Official Employee
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7K Messages
5 years ago
Hi DangerClose3. We appreciate you visiting and posting on the Xfinity Forums. I can assist with troubleshooting your internet connectivity issues. Please reach out to me via private message and include your full name and service address so I can access your account. To send a private message: click my name (ComcastJoeTru) to view my profile. Then click the link that says "Send a message" and there you can private message me.
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