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Internet drops out randomly

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Internet drops out randomly

We've been having issues with internet going out for a few minutes to an hour for several months.  I have spoke with tech support several times.  Once they came out and we were told it was the line, then later in August it was the cable box, last month we received a message, while waiting for a technician, that it was a local issue and it had been fixed.  Each time I was told it was our Netgear CM500 modem, until we did some troubleshooting and realized it was not.

Internet still goes out.  Attached are error logs and readings from my modem.

ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM2561459000000 Hz-3.7 dBmV42.2 dB248585783
2LockedQAM2562465000000 Hz-4.4 dBmV41.6 dB304147420
3LockedQAM2563471000000 Hz-4.5 dBmV41.5 dB260167884
4LockedQAM2564477000000 Hz-4.9 dBmV41.1 dB294747073
5LockedQAM2565483000000 Hz-5.5 dBmV40.6 dB379719149
6LockedQAM2566489000000 Hz-5.8 dBmV40.3 dB3546312225
7LockedQAM2567495000000 Hz-6.3 dBmV40.1 dB7927518518
8LockedQAM2569525000000 Hz-6.6 dBmV39.8 dB172475100
9LockedQAM25615561000000 Hz-6.9 dBmV39.6 dB175964641
10LockedQAM25616567000000 Hz-6.9 dBmV39.6 dB99794141
11LockedQAM25618579000000 Hz-5.5 dBmV40.2 dB51312506
12LockedQAM25619585000000 Hz-5.1 dBmV40.4 dB44742464
13LockedQAM25620591000000 Hz-5.7 dBmV40.2 dB49013884
14LockedQAM25621597000000 Hz-6.1 dBmV40 dB42142521
15LockedQAM25622603000000 Hz-6.3 dBmV39.9 dB42482561
16LockedQAM25623609000000 Hz-6.2 dBmV39.9 dB36562932
 
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA45120 Ksym/sec36500000 Hz47.8 dBmV
2LockedATDMA15120 Ksym/sec17300000 Hz47 dBmV
3LockedATDMA25120 Ksym/sec23700000 Hz47.3 dBmV
4LockedATDMA35120 Ksym/sec30100000 Hz

49 dBmV

 

 

TimePriorityDescription
2020-11-14, 08:14:45Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 08:14:26Notice (6)Honoring MDD; IP provisioning mode = IPv6
2020-11-14, 08:14:12Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 08:09:34Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 08:08:27Notice (6)Honoring MDD; IP provisioning mode = IPv6
2020-11-14, 08:08:15Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:57:34Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:54:49Notice (6)Honoring MDD; IP provisioning mode = IPv6
2020-11-14, 07:54:37Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.0;CM-VER=3.0;
2020-11-14, 07:54:15Critical (3)No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.0;CM-VER=3.0;
2020-11-14, 07:54:06Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:49:50Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:49:50Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:49:50Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:49:26Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:49:22Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:49:22Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 07:48:14Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:56:38Notice (6)Honoring MDD; IP provisioning mode = IPv6
2020-11-14, 06:56:29Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-11-14, 06:56:06Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:52:07Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:52:07Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:52:07Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:52:06Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:52:06Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:38:28Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:30Notice (6)Honoring MDD; IP provisioning mode = IPv6
1970-1-1, 00:00:21Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-11-14, 06:36:39Critical (3)Resetting the cable modem due to docsDevResetNow
2020-11-14, 06:35:02Critical (3)No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.0;CM-VER=3.0;
2020-11-14, 06:34:50Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:33:59Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:32:44Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:28:05Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:28:01Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:28:01Critical (3)Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:26:53Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.1;CM-VER=3.0;
2020-11-14, 06:12:59Critical (3)No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:01:5c:a6:ec:60;CM-QOS=1.0;CM-VER=3.0;
2020-11-14, 06:12:54Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:fe:09:68;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

 

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Expert

Re: Internet drops out randomly

The upstream power is on the high side on channel number 4, and it may be intermittently fluctuating even higher to out of spec levels. The downstream power is on the weak side as well. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

You may want to get the techs re-involved until it is fixed properly.

 

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.
Good luck !



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