Sudden Onset Frequent T3/T4 Timeouts (SOFTTT)

[Petti351]

Hi folks. Over the past two or three weeks my connection has suddenly begun disconnecting frequently. I read enough to learn about the event log and found that the drops are illustrated by T3 and T4 timeout errors. Nothing about the wiring or the hardware in the house has changed. I tried eliminating a splitter, and that had no effect. Cables look good, connections are tight, modem (Netgear C3000-100NAS) stats seem ok during normal operation.

Downstream:

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectables
1	Locked	QAM256	13	507000000 Hz	9.6 dBmV	43.9 dB	0	0
2	Locked	QAM256	9	477000000 Hz	9.8 dBmV	43.9 dB	0	0
3	Locked	QAM256	10	483000000 Hz	9.8 dBmV	43.9 dB	0	0
4	Locked	QAM256	11	489000000 Hz	9.8 dBmV	43.9 dB	0	0
5	Locked	QAM256	12	495000000 Hz	10.1 dBmV	44.6 dB	0	0
6	Locked	QAM256	14	513000000 Hz	9.6 dBmV	43.9 dB	0	0
7	Locked	QAM256	15	519000000 Hz	9.5 dBmV	43.9 dB	0	0
8	Locked	QAM256	16	525000000 Hz	9.4 dBmV	43.8 dB	0	0

Upstream:

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	3	5120 Ksym/sec	23700000 Hz	45.7 dBmV
2	Locked	ATDMA	1	5120 Ksym/sec	36500000 Hz	45.3 dBmV
3	Locked	ATDMA	2	5120 Ksym/sec	30100000 Hz	44.8 dBmV
4	Locked	ATDMA	4	5120 Ksym/sec	17300000 Hz	44.8 dBmV

Here is the log this morning:

Time	Priority	Description
2020-7-1, 11:01:09	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:55:53	Warning (5)	Unicast DSID PSN startup error
2020-7-1, 10:55:27	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
2020-7-1, 10:55:13	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.0;CM-VER=3.0;
2020-7-1, 10:55:01	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:54:53	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:54:48	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:54:42	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:54:41	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:54:32	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:54:28	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:54:12	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:54:08	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:53:33	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:53:01	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:52:33	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:52:28	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:52:12	Warning (5)	Dynamic Range Window violation
2020-7-1, 10:44:22	Warning (5)	Unicast DSID PSN startup error
1970-1-1, 00:01:04	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
1970-1-1, 00:00:36	Notice (6)	WiFi Interface [wl0] set to Channel 6 (Side-Band Channel:10) - Reason:INIT
1970-1-1, 00:00:33	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-7-1, 10:42:28	Critical (3)	Resetting the cable modem due to docsDevResetNow
2020-7-1, 10:42:09	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:32	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2020-7-1, 10:39:31	Critical (3)	Resetting the cable modem due to docsDevResetNow
2020-7-1, 10:29:26	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.0;CM-VER=3.0;
2020-7-1, 10:29:13	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:29:01	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:28:46	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:28:41	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:28:14	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:28:13	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:27:41	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:26:33	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:26:01	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 10:05:36	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 09:59:36	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 09:59:04	Critical (3)	Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;
2020-7-1, 09:57:38	Critical (3)	Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=b0:7f:b9:e0:e7:10;CMTS-MAC=00:56:2b:76:c4:ee;CM-QOS=1.1;CM-VER=3.0;

Does anything stand out? Thanks for reading!

[Petti351]

I'd also like to add that I've tried resetting the modem many times, renewing the IP lease, gone through all the FAQ's and the Xfinity AI chat thing which tries to reset the modem and then just Error 500's out every time. Not very useful.

[Petti351]

Double tap due to, you guessed it, a timeout error!

[Petti351]

Update: Got through to customer service today. They could not detect an issue despite a timeout occurring while I was on the line with them, but assured me that they'd monitor my connection and trigger an automated call should my connection go down. There have been at least 11 T3 or T4 timeouts since (about an hour and a half ago), and no call. Not looking hopeful.