Internet keeps dropping

My internet keeps dropping throughout the day for several minutes.

Looking at the logs (I run Netgear CM1000), I can see the following when my connection gets interrupted:

Started Unicast Maintenance Ranging - No Response received - T3 time-out

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received

OR

UCD invalid or channel unusable

No Ranging Response received - T3 time-out

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EG

Expert

•

115.6K Messages

22 hours ago

What do the modem's signal status values look like ? Try getting them here; http://192.168.100.1

Please 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_qd9rfg

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5 Messages

<tabindex=-1>Startup Procedure</tabindex=-1>

Procedure	Status	Comment
Acquire Downstream Channel	375000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enable	BPI+
IP Provisioning Mode	Honor MDD	IPv6 only

<tabindex=-1>Downstream Bonded Channels</tabindex=-1>

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR / MER	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	QAM256	4	375000000 Hz	5.4 dBmV	43.3 dB	598508900	373	524
2	Locked	QAM256	1	357000000 Hz	5.3 dBmV	43.3 dB	594807091	432	465
3	Locked	QAM256	2	363000000 Hz	5.4 dBmV	43.4 dB	594814322	422	483
4	Locked	QAM256	3	369000000 Hz	5.1 dBmV	43.1 dB	594823106	450	394
5	Locked	QAM256	5	381000000 Hz	5.2 dBmV	43.0 dB	594831714	397	374
6	Locked	QAM256	6	387000000 Hz	5.5 dBmV	43.4 dB	594838909	446	408
7	Locked	QAM256	7	393000000 Hz	5.6 dBmV	43.3 dB	594848358	308	371
8	Locked	QAM256	8	399000000 Hz	5.5 dBmV	43.4 dB	594856476	290	376
9	Locked	QAM256	9	405000000 Hz	5.5 dBmV	43.4 dB	594865529	308	339
10	Locked	QAM256	10	411000000 Hz	5.4 dBmV	43.3 dB	594873855	376	331
11	Locked	QAM256	11	417000000 Hz	5.0 dBmV	43.3 dB	594883413	304	345
12	Locked	QAM256	12	423000000 Hz	5.0 dBmV	43.1 dB	594890988	338	327
13	Locked	QAM256	13	429000000 Hz	5.2 dBmV	43.2 dB	594899466	262	324
14	Locked	QAM256	14	435000000 Hz	5.4 dBmV	43.4 dB	594907908	339	311
15	Locked	QAM256	15	441000000 Hz	5.2 dBmV	43.3 dB	594917819	312	267
16	Locked	QAM256	16	447000000 Hz	5.0 dBmV	43.3 dB	594926493	262	311
17	Locked	QAM256	17	453000000 Hz	5.0 dBmV	43.3 dB	594934676	312	279
18	Locked	QAM256	18	459000000 Hz	4.9 dBmV	43.2 dB	594943023	262	255
19	Locked	QAM256	19	465000000 Hz	5.0 dBmV	43.1 dB	594951152	259	288
20	Locked	QAM256	20	471000000 Hz	5.1 dBmV	43.3 dB	594960017	284	224
21	Locked	QAM256	21	477000000 Hz	5.3 dBmV	42.7 dB	594968221	292	248
22	Locked	QAM256	22	483000000 Hz	5.2 dBmV	42.6 dB	594976621	280	254
23	Locked	QAM256	23	489000000 Hz	5.2 dBmV	43.0 dB	594984887	262	244
24	Locked	QAM256	24	495000000 Hz	5.0 dBmV	43.0 dB	594993567	213	235
25	Locked	QAM256	25	501000000 Hz	5.1 dBmV	43.2 dB	595001381	271	226
26	Locked	QAM256	26	507000000 Hz	5.3 dBmV	43.1 dB	595009921	250	211
27	Locked	QAM256	27	513000000 Hz	5.4 dBmV	42.9 dB	595018810	227	230
28	Locked	QAM256	28	519000000 Hz	5.5 dBmV	42.8 dB	595018989	242	211
29	Locked	QAM256	29	525000000 Hz	5.3 dBmV	43.0 dB	595037769	234	197
30	Locked	QAM256	30	531000000 Hz	5.2 dBmV	43.1 dB	595042704	212	201
31	Locked	QAM256	31	537000000 Hz	5.0 dBmV	42.6 dB	595039141	239	178
32	Locked	QAM256	32	543000000 Hz	5.2 dBmV	43.0 dB	595040692	217	157

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>

Channel	Lock Status	Modulation	Channel ID	Frequency	Power
1	Locked	ATDMA	17	16400000 Hz	42.5 dBmV
2	Locked	ATDMA	18	22800000 Hz	42.5 dBmV
3	Locked	ATDMA	19	29200000 Hz	43.3 dBmV
4	Locked	ATDMA	20	35600000 Hz	43.5 dBmV
5	Not Locked	Unknown	0	0 Hz	0.0 dBmV
6	Not Locked	Unknown	0	0 Hz	0.0 dBmV
7	Not Locked	Unknown	0	0 Hz	0.0 dBmV
8	Not Locked	Unknown	0	0 Hz	0.0 dBmV

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power	SNR / MER	Active Subcarrier Number Range	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	0, 1, 2, 3	193	690000000 Hz	5.3 dBmV	40.0 dB	148 ~ 3947	132639553	110597350	926
2	Locked	0, 1, 2, 3	194	957000000 Hz	3.9 dBmV	40.3 dB	148 ~ 3947	133616952	106837644	131

<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power
1	Not Locked	Unknown	0	0 Hz	0 dBmV
2	Not Locked	Unknown	0	0 Hz	0 dBmV

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21 hours ago

0

user_qd9rfg

Visitor

•

5 Messages

21 hours ago

<tabindex=-1>Startup Procedure</tabindex=-1>

Procedure	Status	Comment
Acquire Downstream Channel	375000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enable	BPI+
IP Provisioning Mode	Honor MDD	IPv6 only

<tabindex=-1>Downstream Bonded Channels</tabindex=-1>

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR / MER	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	QAM256	4	375000000 Hz	5.4 dBmV	43.3 dB	598508900	373	524
2	Locked	QAM256	1	357000000 Hz	5.3 dBmV	43.3 dB	594807091	432	465
3	Locked	QAM256	2	363000000 Hz	5.4 dBmV	43.4 dB	594814322	422	483
4	Locked	QAM256	3	369000000 Hz	5.1 dBmV	43.1 dB	594823106	450	394
5	Locked	QAM256	5	381000000 Hz	5.2 dBmV	43.0 dB	594831714	397	374
6	Locked	QAM256	6	387000000 Hz	5.5 dBmV	43.4 dB	594838909	446	408
7	Locked	QAM256	7	393000000 Hz	5.6 dBmV	43.3 dB	594848358	308	371
8	Locked	QAM256	8	399000000 Hz	5.5 dBmV	43.4 dB	594856476	290	376
9	Locked	QAM256	9	405000000 Hz	5.5 dBmV	43.4 dB	594865529	308	339
10	Locked	QAM256	10	411000000 Hz	5.4 dBmV	43.3 dB	594873855	376	331
11	Locked	QAM256	11	417000000 Hz	5.0 dBmV	43.3 dB	594883413	304	345
12	Locked	QAM256	12	423000000 Hz	5.0 dBmV	43.1 dB	594890988	338	327
13	Locked	QAM256	13	429000000 Hz	5.2 dBmV	43.2 dB	594899466	262	324
14	Locked	QAM256	14	435000000 Hz	5.4 dBmV	43.4 dB	594907908	339	311
15	Locked	QAM256	15	441000000 Hz	5.2 dBmV	43.3 dB	594917819	312	267
16	Locked	QAM256	16	447000000 Hz	5.0 dBmV	43.3 dB	594926493	262	311
17	Locked	QAM256	17	453000000 Hz	5.0 dBmV	43.3 dB	594934676	312	279
18	Locked	QAM256	18	459000000 Hz	4.9 dBmV	43.2 dB	594943023	262	255
19	Locked	QAM256	19	465000000 Hz	5.0 dBmV	43.1 dB	594951152	259	288
20	Locked	QAM256	20	471000000 Hz	5.1 dBmV	43.3 dB	594960017	284	224
21	Locked	QAM256	21	477000000 Hz	5.3 dBmV	42.7 dB	594968221	292	248
22	Locked	QAM256	22	483000000 Hz	5.2 dBmV	42.6 dB	594976621	280	254
23	Locked	QAM256	23	489000000 Hz	5.2 dBmV	43.0 dB	594984887	262	244
24	Locked	QAM256	24	495000000 Hz	5.0 dBmV	43.0 dB	594993567	213	235
25	Locked	QAM256	25	501000000 Hz	5.1 dBmV	43.2 dB	595001381	271	226
26	Locked	QAM256	26	507000000 Hz	5.3 dBmV	43.1 dB	595009921	250	211
27	Locked	QAM256	27	513000000 Hz	5.4 dBmV	42.9 dB	595018810	227	230
28	Locked	QAM256	28	519000000 Hz	5.5 dBmV	42.8 dB	595018989	242	211
29	Locked	QAM256	29	525000000 Hz	5.3 dBmV	43.0 dB	595037769	234	197
30	Locked	QAM256	30	531000000 Hz	5.2 dBmV	43.1 dB	595042704	212	201
31	Locked	QAM256	31	537000000 Hz	5.0 dBmV	42.6 dB	595039141	239	178
32	Locked	QAM256	32	543000000 Hz	5.2 dBmV	43.0 dB	595040692	217	157

<tabindex=-1>Upstream Bonded Channels</tabindex=-1>

Channel	Lock Status	Modulation	Channel ID	Frequency	Power
1	Locked	ATDMA	17	16400000 Hz	42.5 dBmV
2	Locked	ATDMA	18	22800000 Hz	42.5 dBmV
3	Locked	ATDMA	19	29200000 Hz	43.3 dBmV
4	Locked	ATDMA	20	35600000 Hz	43.5 dBmV
5	Not Locked	Unknown	0	0 Hz	0.0 dBmV
6	Not Locked	Unknown	0	0 Hz	0.0 dBmV
7	Not Locked	Unknown	0	0 Hz	0.0 dBmV
8	Not Locked	Unknown	0	0 Hz	0.0 dBmV

<tabindex=-1>Downstream OFDM Channels</tabindex=-1>

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power	SNR / MER	Active Subcarrier Number Range	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	0, 1, 2, 3	193	690000000 Hz	5.3 dBmV	40.0 dB	148 ~ 3947	132639553	110597350	926
2	Locked	0, 1, 2, 3	194	957000000 Hz	3.9 dBmV	40.3 dB	148 ~ 3947	133616952	106837644	131

<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>

Channel	Lock Status	Modulation / Profile ID	Channel ID	Frequency	Power
1	Not Locked	Unknown	0	0 Hz	0 dBmV
2	Not Locked	Unknown	0	0 Hz	0 dBmV

0

0

EG

Expert

•

115.6K Messages

20 hours ago

The signal status values were good at that snapshot in time. Please post the modem's RF error log entries in their entirety (copy and paste all of the text), but redact the CM and the CMTS MAC addresses for privacy or else the forum bot will not allow your post to be seen publicly.

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EG

Expert

•

115.6K Messages

2 hours ago

Quite welcome ! Yuck ! The error log entries indicate 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 those upstream receive signal stats.

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

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