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Netgear AC1900 C7000v2 Downstream Light Flashing
I have had the same provider (Xfinity) and the same modem router for about 14 months. I had never had this problem before, but starting last week somewhere around 5 times a day the downstream ligh...
Power levels are too high. https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
Get you a -6dbm coax cable line attenuator between the modem and coax line.
Got some correctables and un-correctables however not horrible. Should be mostly zeros.
Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box.
Be sure your using good quality RG6 coax cable up to the modem.
Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
Be sure to power OFF the modem for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html
https://highspeed.tips/docsis-events/
| 2025-8-25, 13:57:20 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 13:57:20 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 13:57:20 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 13:57:20 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 13:52:30 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 13:52:30 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 13:51:03 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 13:51:03 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:58:52 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:58:52 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:58:52 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:58:51 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:42:05 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:42:05 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:40:57 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:40:57 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:29:19 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 12:29:19 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 11:26:44 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 11:26:43 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 10:20:49 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 10:20:49 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 10:20:49 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 10:20:49 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 10:13:11 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 10:13:11 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 10:13:11 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 09:11:49 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 09:11:49 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 09:11:49 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 09:11:49 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 08:08:20 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
| 2025-8-25, 08:08:20 | Warning (5) | MDD message timeout;CM-MAC=54:07:7d:ba:ac:0e;CMTS-MAC=00:01:5c:a7:5a:7b;CM-QOS=1.1;CM-VER=3.0; |
These timestamps found in the event log seem to correlate with the outages, but I am not familiar enough with networking to understand what they mean. Assuming this is the key here, based on other approaches it seems the solution is to troubleshoot with ISP but the tech won't know much about it. Is that understanding correct?
Please post a copy and paste of the modems connection status log page.
https://kb.netgear.com/30007/How-do-I-obtain-the-cable-connection-information-from-a-NETGEAR-cable-modem-modem-routerAny Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP. Indicates a signal issue on the ISP line up to the modem.