Re: Connection issues with c6250

anothernetizen · ‎2024-06-12

My router is having intermittent connection issues. Periodically it'll just cut out and I won't have a connection for 5 minutes or so before it comes back. On the bottom, it's labeled as a Netgear AC1600 Wi-Fi Cable Modem Router, model C6250. I've had it since late 2018 and it's worked fun up until several months ago when the issues started appearing. I've posted a copy of the event log from the last couple days. I don't understand any of it, so any help with it would be appreciated.

2024-6-12, 09:15:54	Warning (5)	Dynamic Range Window violation
2024-6-12, 09:15:36	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:59	Warning (5)	Dynamic Range Window violation
2024-6-12, 08:59:58	Notice (6)	WiFi Interface [wl0] set to Channel 6 (Side-Band Channel:N/A) - Reason:INTERFERENCE
2024-6-12, 08:59:58	Warning (5)	Dynamic Range Window violation
2024-6-12, 08:59:57	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.9;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.8;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.7;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.6;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.5;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.4;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.3;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.2;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 08:59:55	Error (4)	Missing BP Configuration Setting TLV Type: 17.1;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:39	Warning (5)	DHCP WARNING - Non-critical field invalid in response ;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:36	Notice (6)	Honoring MDD; IP provisioning mode = IPv4
1970-1-1, 00:00:31	Notice (6)	WiFi Interface [wl1] set to Channel 153 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:31	Notice (6)	WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INIT
1970-1-1, 00:00:29	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-6-12, 06:36:31	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 06:35:41	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 06:35:41	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 06:34:10	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 05:17:55	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-12, 03:57:58	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 22:12:42	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2024-6-11, 22:12:39	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 22:04:24	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 07:41:14	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 07:32:35	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 07:16:37	Critical (3)	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 07:16:37	Critical (3)	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 07:14:41	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 07:10:21	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 06:58:23	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 06:45:44	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 06:27:19	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;
2024-6-11, 06:26:55	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=3c:37:86:03:5b:90;CMTS-MAC=00:01:5c:87:44:71;CM-QOS=1.1;CM-VER=3.0;

FURRYe38 · ‎2024-06-12

Please post a copy and paste of the modems connection status page.
https://kb.netgear.com/30007/How-do-I-obtain-the-cable-connection-information-from-a-NETGEAR-cable-m...

Any 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.

anothernetizen · ‎2024-06-12

This is what I'm seeing:

Procedure	Status	Comment
Acquire Downstream Channel	597000000 Hz	Locked
Connectivity State	OK	Operational
Boot State	OK	Operational
Security	Enabled	BPI+
IP Provisioning Mode	Honor MDD	honorMdd(4)

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectables
1	Locked	QAM256	12	597000000 Hz	0.8 dBmV	40.1 dB	36	167
2	Locked	QAM256	1	531000000 Hz	1.9 dBmV	40.2 dB	39	139
3	Locked	QAM256	4	549000000 Hz	1.6 dBmV	40.3 dB	45	248
4	Locked	QAM256	5	555000000 Hz	1.4 dBmV	40.3 dB	21	136
5	Locked	QAM256	6	561000000 Hz	1.4 dBmV	40.2 dB	75	312
6	Locked	QAM256	7	567000000 Hz	1.4 dBmV	40.2 dB	32	165
7	Locked	QAM256	8	573000000 Hz	1.4 dBmV	40.2 dB	62	191
8	Locked	QAM256	9	579000000 Hz	1.1 dBmV	40.1 dB	30	187
9	Locked	QAM256	10	585000000 Hz	1.1 dBmV	40.1 dB	30	124
10	Locked	QAM256	11	591000000 Hz	1 dBmV	40.1 dB	40	164
11	Locked	QAM256	13	603000000 Hz	0.7 dBmV	40.1 dB	40	220
12	Locked	QAM256	14	609000000 Hz	0.8 dBmV	40.1 dB	45	197
13	Locked	QAM256	17	651000000 Hz	0.5 dBmV	40 dB	30	150
14	Locked	QAM256	23	687000000 Hz	0.7 dBmV	40 dB	39	175
15	Locked	QAM256	24	693000000 Hz	0.7 dBmV	40.1 dB	52	195
16	Locked	QAM256	28	717000000 Hz	1.1 dBmV	40.1 dB	39	103

Upstream Bonded Channels (Partial Service)

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Not Locked	Unknown	5	0 Ksym/sec	38000000 Hz	0.0 dBmV
2	Locked	ATDMA	6	5120 Ksym/sec	31600000 Hz	45.5 dBmV
3	Not Locked	Unknown	7	0 Ksym/sec	25200000 Hz	0.0 dBmV
4	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV

FURRYe38 · ‎2024-06-12

Ok power levels are good.

However you have correctables and un-correctables that 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-Mod...
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html
https://highspeed.tips/docsis-events/

anothernetizen · ‎2024-06-12

Thank you! I'll give all that a try. Will report back here if there continues to be any issues.

FURRYe38 · ‎2024-06-12

👍

plemans · ‎2024-06-12

Your logs are indicating a line issues.

The problem with the C6250 is that is only a 16x4 modem.

meaning it doesn't cover all the channels and modems like to switch between channels.

So it might look fine now, but not all of them might be.

Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, and 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.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISPs charge if the wiring issue is in the home. So this helps prevent this.

If that doesn't help, the ISP needs to check the line.

You might also check into upgrading at some point. The C6250 is getting older/slower/depreciated. Its coming up on time to upgrade to docsis 3.1 and a different router (prefer modem separate from the router in my experience).