Continuous Random Modem Reboots - Multiple T3/T4 Errors

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For the past 5 months, my internet has randomly dropped.  It happens 10-20 times per day 4-5 days a week.  It usually happens between 7am-5pm.  Sometimes it comes back on it’s own, but most of the time I have to reboot the modem and router.   I have checked that all my connections are tight, there are no splitters on my line, and I see no cuts/tears in the coax cables.  I have also factory reset both my modem and my router.  I’ve also hard wired to my router as well as directly to my modem. I’ve tried two different modems.

When my internet is working, I get good speeds at both my modem and my router (500-600 mbps down/ 15-17 mbps up).  I’ve checked the diagnostics page of my modem and my downstream channels are all bonded, power levels are usually -4 to +4 dBmV and SNR is 38.5 to 39.5 dB.  Upstream channels are bonded, ATDMA 5120 Ksym/sec, and power is usually 40 to 42 dBmV.

The event log has shown that there’s been T3 errors multiple times before internet drops, usually there is also a T4 error.  Lately there have been more T4.

After rebooting modem, the internet will be good for anywhere between ten minutes to a couple hours, but then the T3/T4 errors occur again and I have to reboot modem again or wait long enough for it to reboot itself.

A few months ago, back in Apr 2020, a couple of Xfinity employees let me know they’d be replacing a line in front of my house and would need to cut my grass to access it.  The problems I’ve described have been more noticeable since then, but it could be coincidence.   

I contacted customer service via Chat at the end of Jun and the rep had me reboot modem, they resent signal, etc.  The issue still existed and the modem actually lost connection during my chat session and I had to connect to my phone hotspot.  They ended up telling me they couldn’t do more and before they would request a technician service call but before that could be scheduled I would get a call to do a virtual technician session.  I never received a call or visit from a physical technician either.

I spent the next few days trying everything I could think of to troubleshoot more.  I took my modem and my laptop outside and connected modem to the line coming directly from the Comcast box attached to my house in order to eliminate the cabling from the Xfinity connection to my modem as the issue.  The power was very high there, 8 to 9 dBmv, which is probably too strong and would cause a modem reboot quickly.  So, I took my modem back inside to the original spot and connected my laptop directly to the modem and ran some speed tests and watched the diagnostics page and noticed that channels 46 and 47 quickly had very high correctables and uncorrectables and soon the modem rebooted.  I rebooted until the modem was bonded to other channels that didn’t include 46 and 47.  I noticed my modem will bond to 1 of 3 groups of channels: 8-23, 20-35, or 32-47.  20-35 appeared to not have many correctables/uncorrectables so I left it on that.  I then had no issues for 3-4 weeks straight and the last time I checked the  modem diagnostics page showed uptime of 23 days!  …but our electric power went out, so I don’t know exactly how many days the modem was actually up.   Fast forward to middle of Aug and all the issues started again and now regardless of which groups of channels get bonded, the modem has had a lot of T3 and T4 errors and the modem reboots many times throughout the day and now it happens multiple times in the evening as well.

Today, I sat here for over an hour and took screenshots of the diagnostics page to see how quickly the uncorrectables increased.  Channel 46 is jumping up quickly.

I’m at my wits end and need Xfinity’s service to help resolve this.  Either it’s something with my cabling that I am not able to tell by visual inspection, or it’s ingress on other part of lines before getting to my house.

Can Xfinity experts please look at the CMTS to confirm issues and if so, schedule a technician visit?

Here are the current Modem diagnostics Info:

Event Log:

Wed Sep 02 17:53:48 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 17:53:48 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 17:53:48 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 17:54:17 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 17:54:17 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 17:54:17 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 17:54:24 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 17:58:44 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Wed Sep 02 19:19:05 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 19:19:05 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 19:19:05 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 19:19:31 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Wed Sep 02 19:23:52 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Thu Sep 03 13:03:59 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:03:59 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:03:59 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:04:02 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:04:02 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:04:02 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:04:03 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:04:03 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:04:03 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:04:30 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 13:08:50 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Thu Sep 03 14:33:34 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 14:33:34 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 14:33:34 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 14:34:05 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 14:34:05 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 14:34:05 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 14:34:11 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 14:38:31 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:41:50 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:41:50 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:41:50 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:42:10 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:42:10 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:42:10 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:42:25 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 15:46:45 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Thu Sep 03 16:04:14 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 16:04:14 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 16:04:14 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 16:04:19 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 16:04:19 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 16:04:19 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 16:04:21 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 16:08:41 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Thu Sep 03 18:42:51 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 18:42:51 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 18:42:51 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 18:43:20 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 18:43:20 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 18:43:20 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 18:43:23 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 18:47:43 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Thu Sep 03 20:43:35 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 20:43:35 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 20:43:35 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 20:43:58 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 20:43:58 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 20:43:58 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 20:44:13 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Thu Sep 03 20:48:34 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Time Not Established	Critical (3)	No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.0;CM-VER=3.0;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out
Fri Sep 04 04:11:20 2020	Critical (3)	SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:14:42 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:14:42 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:14:42 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:15:16 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:15:16 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:15:16 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:15:21 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:19:41 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:51:31 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:51:31 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:51:31 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:52:00 2020	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:52:01 2020	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:52:01 2020	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Fri Sep 04 10:56:19 2020	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=f8:a0:97:b7:f6:fb;CMTS-MAC=00:01:5c:86:4c:50;CM-QOS=1.1;CM-VER=3.0;
Time Not Established	Notice (6)	Honoring MDD; IP provisioning mode = IPv6

Downstream Bonded Channels
Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Corrected	Uncorrectables
1	Locked	QAM256	32	585000000 Hz	-2.1 dBmV	39.0 dB	477	387
2	Locked	QAM256	33	591000000 Hz	-1.9 dBmV	39.0 dB	508	265
3	Locked	QAM256	34	597000000 Hz	-2.0 dBmV	38.9 dB	511	290
4	Locked	QAM256	35	603000000 Hz	-1.9 dBmV	38.9 dB	563	301
5	Locked	QAM256	36	609000000 Hz	-1.7 dBmV	39.1 dB	556	269
6	Locked	QAM256	37	615000000 Hz	-1.4 dBmV	39.2 dB	468	298
7	Locked	QAM256	38	621000000 Hz	-1.2 dBmV	39.2 dB	551	240
8	Locked	QAM256	39	627000000 Hz	-1.3 dBmV	39.2 dB	473	277
9	Locked	QAM256	40	633000000 Hz	-1.3 dBmV	39.1 dB	456	271
10	Locked	QAM256	41	639000000 Hz	-1.7 dBmV	39.0 dB	377	338
11	Locked	QAM256	42	645000000 Hz	-1.3 dBmV	39.1 dB	429	281
12	Locked	QAM256	43	651000000 Hz	-1.3 dBmV	39.0 dB	475	339
13	Locked	QAM256	44	657000000 Hz	-1.3 dBmV	39.0 dB	482	270
14	Locked	QAM256	45	663000000 Hz	-1.4 dBmV	39.1 dB	452	340
15	Locked	QAM256	46	669000000 Hz	-1.2 dBmV	39.2 dB	53790	179652
16	Locked	QAM256	47	675000000 Hz	-1.3 dBmV	38.8 dB	9263	19179

Upstream Bonded Channels
Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	44	5120 Ksym/sec	36500000 Hz	41.5 dBmV
2	Locked	ATDMA	41	5120 Ksym/sec	17300000 Hz	40.3 dBmV
3	Locked	ATDMA	42	5120 Ksym/sec	23700000 Hz	40.3 dBmV
4	Locked	ATDMA	43	5120 Ksym/sec	30100000 Hz	41.5 dBmV

Current System Time: Fri Sep 04 12:54:07 2020

Status
Up Time	0 days 01h:58m:23s

[EG]

Even though the signal stats looked o/k at that snapshot in time, the error log entries confirm 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 can check the CMTS (Cable Modem Termination System) for any real time degradation and / or error reports, see your node / cable plant and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.

You should get a reply here in your topic. Good luck !

[00110111]

Thank you!

[ComcastMichael]

Greetings, @00110111! I appreciate you taking the time to reach out to us here on the forums. I hope you are having an amazing day! I apologize to hear of the issues you are running into with your modem rebooting more often than it should. I know how important it is to have a reliable internet connection these days. I work from home myself and rely on my internet connection daily. I would like to see what we can do for you. I appreciate everything you have looked into thus far. Can you please send me a PM with your first and last name so I may further assist you?

To send a private message, please click my name "ComcastMichael" then select "Send a Message" on the right side.