Experiencing WAN outages multiple times per day since June 12

The outage period, as reported on my home network, is approximately 1min 30sec.

Multiple times a day and throughout the date and night.

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user_wtg1dt

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8 Messages

1 day ago

My modem reports UCD invalid or channel unusable errors multiple times a day.

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Please post all of the error log entries in their entirety (copy and paste them, don't post a screenshot) but redact any CM MAC and the CMTS MAC addresses for your privacy. They are considered to be personal information. The posting of personally identifying information is a violation of their forum guidelines. The forum bot will not allow your post to be seen publicly.

Please also copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

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user_wtg1dt

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8 Messages

@EG

Time	Priority	Description
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
18:00:39 Sat Jul 5 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;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=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
21:45:40 Sat Jul 5 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=0;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=:CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;
04:45:38 Sun Jul 6 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=7;CMTS-MAC=;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=;CMTS-MAC=0;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
11:30:35 Sun Jul 6 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=0;CMTS-MAC=;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=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
17:00:35 Sun Jul 6 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;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=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=7;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
15:45:41 Mon Jul 7 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=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:;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
17:15:40 Mon Jul 7 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=7;CMTS-MAC=;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=0;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
21:30:38 Mon Jul 7 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=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=CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
03:30:38 Tue Jul 8 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;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=7;CMTS-MAC=0;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
05:30:27 Tue Jul 8 2025	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
05:30:36 Tue Jul 8 2025	Critical (3)	UCD invalid or channel unusable;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
05:34:23 Tue Jul 8 2025	Notice (6)	CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0.;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;

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1 day ago

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user_wtg1dt

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8 Messages

@EG

Number of Channels Connected
Downstream	25
Upstream	4

(edited)

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1 day ago

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user_wtg1dt

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8 Messages

@EG

Channel	Lock Status	Modulation	Channel ID	Freq. (MHz)	Pwr (dBmV)	SNR (dB)	Corrected	Uncorrected
1	Locked	QAM256	20	975.0	6.7	44.2	0	0
2	Locked	QAM256	1	387.0	6.5	45.2	0	0
3	Locked	QAM256	2	393.0	6.3	45.0	0	0
4	Locked	QAM256	3	399.0	6.1	44.9	0	0
5	Locked	QAM256	4	405.0	6.3	45.0	0	0
6	Locked	QAM256	5	411.0	6.4	44.9	0	0
7	Locked	QAM256	6	417.0	6.6	45.0	0	0
8	Locked	QAM256	7	423.0	6.6	45.1	0	0
9	Locked	QAM256	8	429.0	6.6	45.0	0	0
10	Locked	QAM256	9	435.0	6.5	45.0	0	0
11	Locked	QAM256	10	441.0	6.6	45.0	0	0
12	Locked	QAM256	11	447.0	6.7	45.0	0	0
13	Locked	QAM256	12	453.0	6.7	44.9	0	0
14	Locked	QAM256	13	459.0	6.8	45.0	0	0
15	Locked	QAM256	14	465.0	6.8	44.9	0	0
16	Locked	QAM256	15	471.0	6.9	45.0	0	0
17	Locked	QAM256	16	477.0	6.7	45.0	0	0
18	Locked	QAM256	17	957.0	6.2	44.1	0	0
19	Locked	QAM256	18	963.0	6.4	44.2	0	0
20	Locked	QAM256	19	969.0	6.7	44.2	0	0
21	Locked	QAM256	21	981.0	6.6	44.2	0	0
22	Locked	QAM256	22	987.0	6.6	44.0	0	0
23	Locked	QAM256	23	993.0	6.4	44.0	0	0
24	Locked	QAM256	24	999.0	6.3	43.8	0	0
25	Locked	OFDM PLC	193	774.0	6.7	44.2	794651	0

(edited)

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1 day ago

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EG

Expert

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111.5K Messages

1 day ago

Thank you. The error logs are ugly. The downstreams were in spec at that moment. Are the upstream channel values being shown ? If so, please post them as well.

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user_wtg1dt

Visitor

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8 Messages

@EG

Channel	Lock Status	Channel Type	Channel ID	Symb. Rate (Ksym/sec)	Freq. (MHz)	Pwr (dBmV)
1	Locked	SC-QAM	1	5120	16.4	34.0
2	Locked	SC-QAM	2	5120	22.8	34.5
3	Locked	SC-QAM	3	5120	29.2	35.0
4	Locked	SC-QAM	4	5120	35.6	35.5

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1 day ago

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XfinityDilary

Official Employee

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2.3K Messages

Thanks for providing the logs, user_wtg1dt, and for working with @EG to get this resolved. We appreciate your insight, @EG. Let's take a further look here. Could you please send our team a Direct Message with your name and service address? Our team can help.

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6 hours ago

EG

Expert

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111.5K Messages

6 hours ago

The upstream power values are ok as well. So even though the signal status values looked OK at that snapshot in time, the error log entries confirm 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 values 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 (The Digital Care Team) who are available to these boards. They will be able to poll the CMTS (Cable Modem Termination System) to check 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 check those upstream receive signal stats.

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

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user_wtg1dt

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8 Messages

@EG Much appreciate your assistance!

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5 hours ago

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EG

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111.5K Messages

5 hours ago

@user_wtg1dt

It's my pleasure ! 😊

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Your Home Network

user_wtg1dt

Experiencing WAN outages multiple times per day since June 12

user_wtg1dt

EG

user_wtg1dt

user_wtg1dt

user_wtg1dt

EG

user_wtg1dt

XfinityDilary

EG

user_wtg1dt

EG

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