CM500 dropping connection

eltoman · ‎2021-08-19

Hello, and thank you in advance for your help.

I have had CM500 cable modem for 2+ years. It has worked great until the last week or so when it began losing connection. Initially, I power cycled the unit and it seemed to come back on. At first, it was fine for a couple of days before our connectivity was down again. Then yesterday it went down repeatedly throughout the day.

I am pretty limited in my troubleshooting skills. With the multiple drops yesterday, I power cycled the unit and then logged in to the modem. I've copied the cable connection information as well as a copy of the event log below.

I'm wondering if this is a modem issue or may be an issue with our cable connection. We had some ongoing issues with our ISP (WOW!) a few years ago but they upgraded their service lines in our neighborhood and things have worked consistently well since then. In case this may be relevant, we've had some pretty big rain storms recently and I've wondered if that could affect things.

Thank you for any help you may be able to provide. Please let me know if I can provide any additional information.

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	507000000 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	1	507000000 Hz	-9.9 dBmV	39 dB	0	0
2	Locked	QAM256	2	513000000 Hz	-10 dBmV	35.2 dB	0	0
3	Locked	QAM256	3	519000000 Hz	-11 dBmV	37.7 dB	0	0
4	Locked	QAM256	4	525000000 Hz	-10.7 dBmV	35.6 dB	0	0
5	Locked	QAM256	16	597000000 Hz	-12.1 dBmV	38 dB	0	0
6	Locked	QAM256	19	615000000 Hz	-11.7 dBmV	38.3 dB	12	21
7	Locked	QAM256	20	621000000 Hz	-11.6 dBmV	38.3 dB	33	0
8	Locked	QAM256	21	627000000 Hz	-12 dBmV	38.1 dB	10	23
9	Locked	QAM256	22	633000000 Hz	-11.9 dBmV	38 dB	33	0
10	Locked	QAM256	23	639000000 Hz	-12.5 dBmV	37.6 dB	33	0
11	Locked	QAM256	24	645000000 Hz	-11.7 dBmV	38.2 dB	60	7
12	Locked	QAM256	25	651000000 Hz	-12.2 dBmV	37.9 dB	20	18
13	Locked	QAM256	26	657000000 Hz	-12 dBmV	38 dB	69	1
14	Locked	QAM256	27	663000000 Hz	-12.4 dBmV	37.6 dB	107	26
15	Locked	QAM256	28	669000000 Hz	-12.3 dBmV	37.7 dB	244	80
16	Locked	QAM256	32	693000000 Hz	-12.2 dBmV	37.9 dB	3440	393

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	7	5120 Ksym/sec	31000000 Hz	52.5 dBmV

Current System Time:Thu Aug 19 06:50:57 2021

Time	Priority	Description
2021-8-18, 21:29:33	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.1;CM-VER=3.0;
2021-8-18, 21:29:41	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 21:29:49	Notice (6)	Honoring MDD; IP provisioning mode = IPv4
2021-8-18, 21:29:52	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.1;CM-VER=3.0;
2021-8-18, 21:30:00	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 21:30:09	Notice (6)	Honoring MDD; IP provisioning mode = IPv4
2021-8-18, 21:30:14	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.1;CM-VER=3.0;
2021-8-18, 22:40:26	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.1;CM-VER=3.0;
2021-8-18, 22:41:46	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:41:47	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:42:45	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:42:46	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:43:45	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:43:46	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:44:57	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:44:58	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:45:59	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:46:00	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:46:58	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:46:59	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:48:11	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:48:12	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:49:18	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:49:19	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:50:17	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:50:18	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:51:14	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:51:15	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:52:27	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:52:28	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:53:32	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:53:33	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:54:44	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:54:45	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:55:07	Notice (6)	Honoring MDD; IP provisioning mode = IPv4
2021-8-18, 22:55:10	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.1;CM-VER=3.0;
2021-8-18, 22:55:12	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:55:17	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.0;CM-VER=3.0;
2021-8-18, 22:56:19	Notice (6)	Honoring MDD; IP provisioning mode = IPv4
2021-8-18, 22:56:23	Notice (6)	TLV-11 - unrecognized OID;CM-MAC=14:59:c0:7f:d3:d0;CMTS-MAC=00:01:5c:6a:f8:52;CM-QOS=1.1;CM-VER=3.0;

plemans · ‎2021-08-19

Are you using any splitters or signal attenuators in your line? you''re below optimial spec on your power.

If you have those, remove them. With being below spec, if it varies to low, you'll have issues. And that signal strength can change throughout the day.

Your logs indicate line issues and your power levels show you as low. so I'd check the line for anything that can decrease power. Like the signal attenuator or splitter. Also check the line for kinks, damage, loose/old/bad/corroded connectors, or extended runs.

CM500 dropping connection

CM500 dropping connection

Re: CM500 dropping connection