Recent regular interruptions with "Maintenance Ranging - No Response" errors

Over the last past 7 days, we have been experiencing regular cable internet drop-outs. Sometimes as often as twice an hour. Restarting the modem generally fixes things for a short time, however the interruptions continue. Unfortunately most of the time it is happening in the middle of a school or work video conference. I would appreciate some assistance.

For reference, here are some cable modem logs from today:

2020-10-19, 12:03:07    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-19, 10:39:47    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-19, 10:39:47    Critical (3)    Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-19, 09:41:03    Critical (3)    Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-19, 09:38:21    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-19, 09:33:25    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-19, 08:51:12    Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;

Notes:

* All times seem to be behind by one hour PST.

* I wasn't sure if the MAC references were sensitive, so I ✂ them.

* This is the first time we've experienced any issues like this - it's been rock solid for 3+ years.

This conversation is no longer open for comments or replies and is no longer visible to community members.

Responses

EG

Expert

•

103.5K Messages

4 years ago

@qubian wrote:

I am replying using a wired ethernet connection. The other devices in the house use Wifi.

The question would be, does a computer / device hardwired directly to the router / gateway device with an ethernet cable have the same problem as the WiFi connected devices ?

With this test, we are trying to isolate this from being either a WiFi-only problem or a problem with the general connection to the Comcast system which would of course affect both. It's a good first step of troubleshooting before we proceed any further.

EG

Expert

•

103.5K Messages

4 years ago

The time is normal. Modems don't do DST.

~~Please also post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.~~

What is the exact make and model number of the modem ?

Is this a WiFi connection ?

qubian

New Poster

•

6 Messages

4 years ago

For reference, here are the current cable connection stats:

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	651000000 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	37	651000000 Hz	1.1 dBmV	39.8 dB	0	0
2	Locked	QAM256	21	555000000 Hz	2.1 dBmV	40.2 dB	0	0
3	Locked	QAM256	22	561000000 Hz	2 dBmV	39.4 dB	0	0
4	Locked	QAM256	23	567000000 Hz	2.1 dBmV	40.1 dB	0	0
5	Locked	QAM256	24	573000000 Hz	2.2 dBmV	40.1 dB	0	0
6	Locked	QAM256	25	579000000 Hz	2.2 dBmV	40 dB	0	0
7	Locked	QAM256	26	585000000 Hz	2.1 dBmV	39.6 dB	0	0
8	Locked	QAM256	27	591000000 Hz	1.9 dBmV	39.6 dB	0	0
9	Locked	QAM256	28	597000000 Hz	2 dBmV	39.7 dB	0	0
10	Locked	QAM256	29	603000000 Hz	2 dBmV	39.7 dB	0	0
11	Locked	QAM256	30	609000000 Hz	2 dBmV	39.8 dB	0	0
12	Locked	QAM256	31	615000000 Hz	1.7 dBmV	39.7 dB	0	0
13	Locked	QAM256	32	621000000 Hz	1.6 dBmV	39.9 dB	0	0
14	Locked	QAM256	33	627000000 Hz	1.4 dBmV	39.9 dB	0	0
15	Locked	QAM256	34	633000000 Hz	1.4 dBmV	40 dB	0	0
16	Locked	QAM256	35	639000000 Hz	1.5 dBmV	39.6 dB	0	0
17	Locked	QAM256	36	645000000 Hz	0.7 dBmV	39.9 dB	0	0
18	Locked	QAM256	38	657000000 Hz	0.4 dBmV	39.5 dB	0	0
19	Locked	QAM256	39	663000000 Hz	0.3 dBmV	39.4 dB	0	0
20	Locked	QAM256	40	669000000 Hz	0.3 dBmV	39.4 dB	0	0
21	Locked	QAM256	41	675000000 Hz	0.3 dBmV	38.6 dB	0	0
22	Locked	QAM256	42	681000000 Hz	0.2 dBmV	39 dB	0	0
23	Locked	QAM256	43	687000000 Hz	-0.1 dBmV	39 dB	0	0
24	Locked	QAM256	44	693000000 Hz	-0.3 dBmV	38.9 dB	0	0

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	4	5120 Ksym/sec	36500000 Hz	40 dBmV
2	Locked	ATDMA	1	5120 Ksym/sec	17300000 Hz	38.5 dBmV
3	Locked	ATDMA	2	5120 Ksym/sec	23700000 Hz	40 dBmV
4	Locked	ATDMA	3	5120 Ksym/sec	30100000 Hz	40 dBmV
5	Locked	ATDMA	5	1280 Ksym/sec	41200000 Hz	37.5 dBmV
6	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
7	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV
8	Not Locked	Unknown	0	0 Ksym/sec	0 Hz	0.0 dBmV

qubian

New Poster

•

6 Messages

4 years ago

That's fair. I will wait for the next drop-out and see if we're affected equally.

qubian

New Poster

•

6 Messages

4 years ago

Good questions @EG .

What is the exact make and model number of the modem ?

Netgear C7000v2

Is this a WiFi connection ?

I am replying using a wired ethernet connection. The other devices in the house use Wifi.

qubian

New Poster

•

6 Messages

4 years ago

OK, it just dropped out at 8:33 AM PST. No internet access was possible wired or wireless, and the modem itself was unreachable during this time. It seems it was frozen. This was in the logs afterwards:

Time	Priority	Description
2020-10-20, 07:33:17	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-20, 07:33:17	Warning (5)	MDD message timeout;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-20, 07:32:32	Critical (3)	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;
2020-10-20, 07:32:32	Warning (5)	MDD message timeout;CM-MAC=✂;CMTS-MAC=✂;CM-QOS=1.1;CM-VER=3.0;

qubian

New Poster

•

6 Messages

4 years ago

I believe I've figured it out. I have removed some unecessary port forwarding rules and things have stabilized. My theory is that three MS Teams and two Zoom video conferences simultaneous seems to have caused a port starvation issue and frozen the modem. The cable sync logs would then be a symptom, not the cause of those issues.

This thread can be closed. I will open a new one if this turns out not to be solved.

EG

Expert

•

103.5K Messages

4 years ago

Hope it holds up for you. Good luck ! Closing this topic.

Your Home Network

qubian

Recent regular interruptions with "Maintenance Ranging - No Response" errors

EG

EG

qubian

qubian

qubian

qubian

qubian

EG

New to the Community?