CM500 intermittent drops with T3/4 timeouts and Dynamic Range Window violation

Question

Hi- I've been having problems for about a month with frequent intermittent connection drops lasting anywhere from 10 seconds to 5 minutes. Cox came out last week to check the lines and determined everything was fine, so they swapped my Netgear CM500 modem with one of their "Panoramic wifi" Arris TG1682G modems. That fixed the issue, so they determined my CM500 modem was faulty. Each modem was connected to my my Netgear R6700v2 router.

I had some time today so reconnected the CM500 modem and called Cox to activate it. Within an hour the connection issues started happening again, with frequent "Dynamic Range Window violation," "Unicast Ranging Received Abort Response - Re-initializing" and "Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out" errors occurring along with connection interuptions.

Connection tables and logs are below. Power levels look good from what I can see, but wondering if anyone sees any other issues. This modem is only 2 years old so I'll be disappointed with Netgear if it's already faulty.

Thanks

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	879000000 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	17	879000000 Hz	4.2 dBmV	39.7 dB	11	66
2	Locked	QAM256	1	783000000 Hz	4 dBmV	40.5 dB	21	55
3	Locked	QAM256	2	789000000 Hz	3.6 dBmV	40.3 dB	14	80
4	Locked	QAM256	3	795000000 Hz	4.1 dBmV	40.5 dB	20	78
5	Locked	QAM256	4	801000000 Hz	4.4 dBmV	40.7 dB	20	88
6	Locked	QAM256	5	807000000 Hz	4.3 dBmV	40.7 dB	14	72
7	Locked	QAM256	7	819000000 Hz	4.9 dBmV	40.9 dB	34	142
8	Locked	QAM256	8	825000000 Hz	4.5 dBmV	40.7 dB	18	55
9	Locked	QAM256	34	363000000 Hz	1.1 dBmV	40.2 dB	8753	454
10	Locked	QAM256	35	369000000 Hz	1.3 dBmV	40.3 dB	7536	373
11	Locked	QAM256	37	381000000 Hz	1.6 dBmV	40.4 dB	5895	209
12	Locked	QAM256	43	417000000 Hz	1.9 dBmV	40.4 dB	2657	94
13	Locked	QAM256	44	423000000 Hz	2.1 dBmV	40.5 dB	2479	96
14	Locked	QAM256	46	435000000 Hz	2.4 dBmV	40.7 dB	1937	72
15	Locked	QAM256	47	441000000 Hz	1.9 dBmV	40.3 dB	1963	142
16	Locked	QAM256	48	447000000 Hz	2.5 dBmV	40.7 dB	1538	97

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	4	5120 Ksym/sec	36800000 Hz	41.5 dBmV
2	Locked	ATDMA	1	5120 Ksym/sec	17600000 Hz	41.5 dBmV
3	Locked	ATDMA	2	5120 Ksym/sec	24000000 Hz	40 dBmV
4	Locked	ATDMA	3	5120 Ksym/sec	30400000 Hz	41 dBmV

Current System Time:Sun Feb 21 21:17:15 2021

2021-2-21, 19:34:50	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=10:0c:6b:76:b8:50;CMTS-MAC=00:27:90:0c:26:3f;CM-QOS=1.1;CM-VER=3.0;
2021-2-21, 20:41:31	Warning (5)	Dynamic Range Window violation
2021-2-21, 20:41:47	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=10:0c:6b:76:b8:50;CMTS-MAC=00:27:90:0c:26:3f;CM-QOS=1.1;CM-VER=3.0;
2021-2-21, 20:41:52	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:76:b8:50;CMTS-MAC=00:27:90:0c:26:3f;CM-QOS=1.1;CM-VER=3.0;
2021-2-21, 20:42:06	Warning (5)	Dynamic Range Window violation
2021-2-21, 20:42:08	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=10:0c:6b:76:b8:50;CMTS-MAC=00:27:90:0c:26:3f;CM-QOS=1.1;CM-VER=3.0;
2021-2-21, 20:42:08	Warning (5)	Dynamic Range Window violation
2021-2-21, 20:48:47	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=10:0c:6b:76:b8:50;CMTS-MAC=00:27:90:0c:26:3f;CM-QOS=1.1;CM-VER=3.0;
2021-2-21, 20:49:19	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=10:0c:6b:76:b8:50;CMTS-MAC=00:27:90:0c:26:3f;CM-QOS=1.1;CM-VER=3.0;

scoobyd · Accepted Answer

UPDATE: Amazon agreed to replace the defective Netgear modem even though it was out of warranty. The replacement modem has been working fine, so it wasn't a wiring or ISP issue. I'm glad Amazon stands behind the products they sell when Netgear would not even talk to me about their defective product without charging a fee for customer support. Let's hope this one lasts more than 2 years.&nbsp;

Forum Discussion

CM500 intermittent drops with T3/4 timeouts and Dynamic Range Window violation

2 Replies