Internet constantly losing connection - Multiple Errors Reported by my Netgear CM1000v2 Cable Modem

Question

Xfinity Internet - 500Mbps Download Package

Netgear - CM1000v2 - Cable Modem - (Firmware v10.01.07)

Internet has been fine for over 4 years, last week connection started to drop out every 2 hours or so. Now it's dropping every 5-10 minutes.

I only use wi-fi for phone etc, everything else is wired. I lose both LAN and wi-fi.

No splitters, all new cables. I first thought it might be the router (Netgear xr300) so I plugged my computer directly into the modem. Did not solve the issue.

Logs and Connection Stats are as follows:

Time	Priority	Description
2024-05-12, 20:09:23	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2024-05-12, 20:08:55	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.
2024-05-12, 20:08:08	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2024-05-12, 19:39:31	Critical (3)	UCD invalid or channel unusable;
2024-05-12, 19:39:31	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;
2024-05-12, 19:39:20	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
2024-05-12, 19:39:15	Critical (3)	UCD invalid or channel unusable;
2024-05-12, 19:38:55	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
2024-05-12, 19:38:41	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
2024-05-12, 19:30:37	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2024-05-12, 19:29:37	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
2024-05-12, 19:19:24	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out
2024-05-12, 19:18:41	Warning (5)	Dynamic Range Window violation
2024-05-12, 19:18:41	Warning (5)	RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;
2024-05-12, 19:14:29	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2024-05-12, 19:10:21	Notice (6)	CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;
2024-05-12, 19:06:03	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2024-05-12, 19:06:03	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;
2024-05-12, 19:06:03	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2024-05-12, 19:03:07	Critical (3)	UCD invalid or channel unusable;
2024-05-12, 19:03:07	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;
2024-05-12, 19:02:57	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
2024-05-12, 19:02:52	Critical (3)	UCD invalid or channel unusable;
2024-05-12, 19:02:30	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
2024-05-12, 19:02:19	Critical (3)	SYNC Timing Synchronization failure - Loss of Sync;
2024-05-12, 19:01:44	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2024-05-12, 19:01:38	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
2024-05-12, 19:01:38	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2024-05-12, 19:01:37	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;
2024-05-12, 19:00:57	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2024-05-12, 19:00:54	Warning (5)	MDD message timeout;
2024-05-12, 19:00:49	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;
2024-05-12, 19:00:45	Warning (5)	MDD message timeout;
2024-05-12, 19:00:45	Notice (6)	CM-STATUS message sent. Event Type Code: 2; Chan ID: 24 26; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;
2024-05-12, 18:51:56	Notice (6)	CM-STATUS message sent. Event Type Code: 24; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;
2024-05-12, 18:48:58	Notice (6)	CM-STATUS message sent. Event Type Code: 16; Chan ID: 193; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 2 3.;
2024-05-12, 18:47:03	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;
2024-05-12, 18:40:16	Warning (5)	Dynamic Range Window violation
2024-05-12, 18:40:16	Warning (5)	RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;
2024-05-12, 18:39:44	Critical (3)	UCD invalid or channel unusable;

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	711000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enable	BPI+
IP Provisioning Mode	Honor MDD	IPv6 only

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR / MER	Unerrored Codewords	Correctable Codewords	Uncorrectable Codewords
1	Locked	QAM256	44	711000000 Hz	12.3 dBmV	43.9 dB	206325110	784	2361
2	Locked	QAM256	13	525000000 Hz	12.3 dBmV	44.4 dB	203460722	4958	8837
3	Locked	QAM256	14	531000000 Hz	12.0 dBmV	44.3 dB	213547814	13059	9223
4	Locked	QAM256	15	537000000 Hz	11.8 dBmV	44.1 dB	203411821	12639	14272
5	Locked	QAM256	16	543000000 Hz	11.9 dBmV	44.4 dB	213606604	13666	8413
6	Locked	QAM256	17	549000000 Hz	12.3 dBmV	44.5 dB	203461579	6788	11153
7	Locked	QAM256	18	555000000 Hz	12.1 dBmV	44.3 dB	213613852	8335	13884
8	Locked	QAM256	19	561000000 Hz	12.0 dBmV	44.2 dB	203502668	4053	8409
9	Locked	QAM256	20	567000000 Hz	12.2 dBmV	44.3 dB	203336530	1124	3219
10	Locked	QAM256	21	573000000 Hz	12.5 dBmV	44.6 dB	203348812	6781	23883
11	Locked	QAM256	22	579000000 Hz	12.4 dBmV	44.4 dB	203356492	732	1760
12	Locked	QAM256	23	585000000 Hz	11.9 dBmV	44.1 dB	203518138	8570	14595
13	Locked	QAM256	24	591000000 Hz	12.0 dBmV	44.0 dB	203376584	812	2573
14	Locked	QAM256	25	597000000 Hz	12.6 dBmV	44.4 dB	203451738	22198	33752
15	Locked	QAM256	26	603000000 Hz	12.6 dBmV	44.4 dB	203395042	838	2305
16	Locked	QAM256	27	609000000 Hz	12.0 dBmV	44.0 dB	213566160	26475	34354
17	Locked	QAM256	28	615000000 Hz	11.8 dBmV	43.9 dB	213711803	8841	7837
18	Locked	QAM256	29	621000000 Hz	12.4 dBmV	44.2 dB	213701708	9835	21587
19	Locked	QAM256	30	627000000 Hz	12.5 dBmV	44.4 dB	203571765	8332	19209
20	Locked	QAM256	31	633000000 Hz	12.0 dBmV	44.1 dB	213740586	6210	7879
21	Locked	QAM256	32	639000000 Hz	11.8 dBmV	43.9 dB	203635059	3871	3688
22	Locked	QAM256	33	645000000 Hz	12.0 dBmV	44.1 dB	213764673	3994	8665
23	Locked	QAM256	34	651000000 Hz	12.3 dBmV	44.4 dB	203641582	3725	8396
24	Locked	QAM256	35	657000000 Hz	11.8 dBmV	44.2 dB	213778657	5145	7024
25	Locked	QAM256	36	663000000 Hz	11.2 dBmV	43.7 dB	203656039	3175	7285
26	Locked	QAM256	37	669000000 Hz	11.2 dBmV	44.0 dB	213802742	3192	4992
27	Locked	QAM256	38	675000000 Hz	11.9 dBmV	44.1 dB	203673324	6119	7038
28	Locked	QAM256	39	681000000 Hz	11.8 dBmV	44.2 dB	213820996	4132	4950
29	Locked	QAM256	40	687000000 Hz	11.2 dBmV	43.8 dB	203697972	3387	6287
30	Locked	QAM256	41	693000000 Hz	11.0 dBmV	43.5 dB	203723180	6760	5507
31	Locked	QAM256	42	699000000 Hz	11.5 dBmV	43.8 dB	203739937	4464	6159
32	Locked	QAM256	43	705000000 Hz	11.8 dBmV	44.1 dB	203758486	3604	3564

Upstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power
1	Locked	ATDMA	17	16400000 Hz	48.3 dBmV
2	Locked	ATDMA	18	22800000 Hz	45.3 dBmV
3	Locked	ATDMA	19	29200000 Hz	47.8 dBmV
4	Locked	ATDMA	20	35600000 Hz	48.5 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

Downstream OFDM Channels

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	957000000 Hz	14.6 dBmV	43.8 dB	148 ~ 3947	51507466	605168	17578
2	Not Locked	0	0	0 Hz	7.9 dBmV	0.0 dB	0 ~ 4095	0	0	0

Upstream OFDMA Channels

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

FURRYe38 · Answer

Power levels are too high:
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
I'd get a -6dbm cable coax line attenuator installed.&nbsp;
&nbsp;
You have tons of correctables and un-correctables that is supposed to be zeros.&nbsp;
Any Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP.&nbsp;Indicates a signal issue on the ISP line up to the modem.
&nbsp;
&nbsp;
Have the ISP check the signal and line quality UP to the modem.&nbsp;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.&nbsp;Be sure your using good quality RG6 coax cable up to the modem.&nbsp;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.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.htmlhttps://highspeed.tips/docsis-events/

band_of_gypsys · Answer

Yeah, good luck getting in contact with someone from Xfinity lol!They make it impossible to actually get a tech or even customer service on the phone.&nbsp;Thanks for the reply! :))

FURRYe38 · Answer

Never have been a fan of that ISP.&nbsp;
Good Luck.

Forum Discussion

Internet constantly losing connection - Multiple Errors Reported by my Netgear CM1000v2 Cable Modem

3 Replies