Why does my superhub reboot frequently? Can be disastrous if giving a zoom talk

[aaronsloman]

For some reason in the last two weeks or so I've lost internet connection without any warning and have to wait while the superhub reboots itself. Obviously this can be very annoying if I am linked to a zoom conference and worse than annoying if I am actually giving a presentation at the time.

[lotharmat · Accepted solution]

It probably won't be rebooting - just losing connection to the CMTS - It looks like a reboot but is actually an attempt to renegotiate channels.

Can you post your Hub status and logs?
Someone should be spot if there is a problem
Navigate to http://192.168.0.1 (or http://192.168.100.1 - if in modem mode)
Don't log in!
Click on 'router status'
Copy/paste the data from each of the tabs. The forum software will remove the MAC addresses for you (you may need to click the 'post' button again).

Also, set up a 'Broadband Quality Monitor'. This will monitor the state of your connection and record any network dropouts etc - You can do this at ThinkBroadband (https://www.thinkbroadband.com/broadband/monitoring/quality)
Give it a while to gather data and then click 'Share Live graph' and paste the 'Direct Link' into the forum!

[aaronsloman]

Information as requested approx 23:00 16 Jun 2021

I shall now try to set up the monitor.

Horizontal separators (=======) inserted here by me.

Router status

Status
Downstream
Upstream
Configuration
Network Log

Refresh data
Cable Modem Status
Item Status Comments
Acquired Downstream Channel (Hz)
299000000

Locked
Ranged Upstream Channel (Hz)
46200029

Locked
Provisioning State
=======================================

Downstream bonded channels
Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
1 299000000 -1.9 40 256 qam 21
2 139000000 2 40 256 qam 1
3 147000000 1.7 40 256 qam 2
4 155000000 1.5 40 256 qam 3
5 163000000 1.4 40 256 qam 4
6 171000000 1.4 40 256 qam 5
7 179000000 1 40 256 qam 6
8 187000000 0.7 40 256 qam 7
9 195000000 0.5 40 256 qam 8
10 203000000 0 38 256 qam 9
11 211000000 -0.2 40 256 qam 10
12 219000000 -0.5 40 256 qam 11
13 227000000 -0.9 38 256 qam 12
14 235000000 -1.5 38 256 qam 13
15 243000000 -2.7 38 256 qam 14
16 251000000 -3.4 38 256 qam 15
17 259000000 -2.5 38 256 qam 16
18 267000000 -2.2 38 256 qam 17
19 275000000 -2 40 256 qam 18
20 283000000 -2 40 256 qam 19
21 291000000 -2 40 256 qam 20
22 307000000 -1.5 40 256 qam 22
23 315000000 -1.9 40 256 qam 23
24 323000000 -2 40 256 qam 24

================================

Downstream bonded channels
Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors
1 Locked 40.3 6 0
2 Locked 40.3 6 0
3 Locked 40.3 19 0
4 Locked 40.3 18 0
5 Locked 40.3 19 0
6 Locked 40.3 5 0
7 Locked 40.3 5 0
8 Locked 40.3 5 0
9 Locked 40.3 7 0
10 Locked 38.9 4 0
11 Locked 40.3 5 0
12 Locked 40.3 6 0
13 Locked 38.9 4 0
14 Locked 38.9 5 0
15 Locked 38.9 7 0
16 Locked 38.9 0 0
17 Locked 38.9 12 0
18 Locked 38.9 6 0
19 Locked 40.3 5 0
20 Locked 40.3 5 0
21 Locked 40.3 4 0
22 Locked 40.3 5 0
23 Locked 40.3 5 0
24 Locked 40.3 6 0

============================

Upstream


Refresh data
Upstream bonded channels
Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
1 46200029 43.5 5120 64 qam 11
2 32599976 43.5 5120 64 qam 13
3 39399996 43.5 5120 64 qam 12
4 53700026 43.5 5120 64 qam 10


Upstream bonded channels
Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
1 ATDMA 0 0 0 0
2 ATDMA 0 0 0 0
3 ATDMA 0 0 0 0
4 ATDMA 0 0 0 0

==============================================

Configuration

|General Configuration
Network access
Allowed
Maximum Number of CPEs
1
Baseline Privacy
Enabled
DOCSIS Mode
Docsis30
Config file
foA,.iyewrkldJKDHSUBsgvca


Primary Downstream Service Flow
SFID 554
Max Traffic Rate 230000061
Max Traffic Burst 42600
Min Traffic Rate 0


Primary Upstream Service Flow
SFID 553
Max Traffic Rate 22000061
Max Traffic Burst 42600
Min Traffic Rate 0
Max Concatenated Burst 42600
Scheduling Type BestEffort

==========================================

Network Log
Time Priority Description
10/06/2021 19:27:38 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:53 Warning! Lost MDD
Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:49 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:49 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:49 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:48 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/06/2021 09:00:38 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
08/06/2021 15:45:23 notice DHCP Renew - lease parameters tftp
file-cmreg-vmdg505-bbt060-b.cm
modified;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
08/06/2021 15:45:23 Error DHCP RENEW WARNING - Field invalid in response v4
option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:35 Warning! Lost MDD
Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:31 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:31 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:30 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/06/2021 07:54:56 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
03/06/2021 22:23:8 notice DHCP Renew - lease parameters tftp
file-cmreg-vmdg505-bbt060-b.cm
modified;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
03/06/2021 22:23:8 Error DHCP RENEW WARNING - Field invalid in response v4
option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 18:05:24 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 16:06:3 Warning! Lost MDD
Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 16:05:59 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 16:05:59 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
========================================

[aaronsloman]

I posted all the following earlier -- but it has somehow disappeared while I was trying to follow instructions to set up an external monitor. I apologise if the following is received twice:

==========================================

Configuration

General Configuration
Network access
Allowed
Maximum Number of CPEs
1
Baseline Privacy
Enabled
DOCSIS Mode
Docsis30
Config file
foA,.iyewrkldJKDHSUBsgvca


Primary Downstream Service Flow
SFID 554
Max Traffic Rate 230000061
Max Traffic Burst 42600
Min Traffic Rate 0


Primary Upstream Service Flow
SFID 553
Max Traffic Rate 22000061
Max Traffic Burst 42600
Min Traffic Rate 0
Max Concatenated Burst 42600
Scheduling Type BestEffort

==========================================
Network Log
Time Priority Description
10/06/2021 19:27:38 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:53 Warning! Lost MDD
Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:49 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:49 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:49 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/06/2021 15:54:48 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
09/06/2021 09:00:38 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
08/06/2021 15:45:23 notice DHCP Renew - lease parameters tftp
file-cmreg-vmdg505-bbt060-b.cm
modified;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
08/06/2021 15:45:23 Error DHCP RENEW WARNING - Field invalid in response v4
option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:35 Warning! Lost MDD
Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:31 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:31 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/06/2021 12:57:30 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
05/06/2021 07:54:56 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
03/06/2021 22:23:8 notice DHCP Renew - lease parameters tftp
file-cmreg-vmdg505-bbt060-b.cm
modified;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
03/06/2021 22:23:8 Error DHCP RENEW WARNING - Field invalid in response v4
option;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 18:05:24 critical No Ranging Response received - T3
time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 16:06:3 Warning! Lost MDD
Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 16:05:59 critical SYNC Timing Synchronization failure - Loss of
Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
01/06/2021 16:05:59 Warning! RCS Partial
Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
==========================================

Now struggling to set up the external monitor...

[aaronsloman]

This link, sent to me by someone on a local linux user group may be relevant:

https://www.techsupportforum.com/threads/solved-modem-constantly-reboots.449812/

This is how it ends:

The tech who fixed it (the 5th one to come out and the first who wasn't lazy and rushing to leave) said that he noticed the barrel was pretty old. He monitored the signal from the old one for a while and noticed that it was very jagged and jumping up and down, which would explain my sudden jump over 50 dBmV. He then replaced that barrel with a new one and monitored the signal from that for a while. The signal appeared to be straight so he told me to keep an eye on everything and to call him if the modem reboots again. Well, since he's left (which was about 18 hours ago) my upstream signal has not budged and is staying at a solid 42.7 dBmV. The downstream is barely moving and is sticking around 12.9-13.4 dBmV. Although the downstream is high he said I should not have problems unless that goes to 15 or above. So it appears as though my problem is solved.

I apologise if that cannot be relevant to my VM connection.

[aaronsloman]

Apologies, forgot to say "thanks" earlier. I hope my reply posted earlier provides a clue.

[aaronsloman]

I've recently reported that I have been experiencing intermittent loss of internet connection via cable -- with VM router rebooting. Cable connection is an external junction box on wall at foot of hedge, in driveway, installed many years ago (when we joined Blueyonder). I now see that the box lid won't stay shut. Could that be related to intermittent loss of connection? I don't know how long it has been in that state. But the loss of connection is fairly recent. I posted details of logs on the forum as requested earlier, but at that stage did not think of mentioning the junction box. Can I request here that someone be sent to check the box?

[SCA1972]

@aaronsloman Please don't create multiple threads for the same issue, it is against the forum rules and makes it very hard for everybody to follow what is happening with your issue.  I have merged your threads.

Your log doesn’t look great, but hard to say without the power levels from the Downstream and Upstream tabs on the status screen.

______________________
Scott

My setup: VM TV box, M350 Fibre broadband with Hub 3 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.

[aaronsloman]

I apologise for rule breaking. I can't recall the exact sequence as some of my activity here was interrupted by an attempt to follow instructions to set up external monitoring, after I had followed instructions for collecting and inserting information into this thread. Trying to set up the external monitoring took some time -- including changing router settings, and setting up an account on the recommended monitoring system, then trying and failing to give it permission to check the connectionn -- after which I had the idea about the external junction box so I came back here to add that to this thread. But I could not find my previous comments so I started a new message -- about the external cable connection. I then tried to find this thread again and failed, so I concluded that everything I had typed in had somehow got deleted. Fortunately I had kept a full record, so I then reinserted it at the old location.

I have no idea how it got deleted -- I thought I had finished sending the message, but perhaps I missed out a final step and a timeout then caused my text to be deleted while I was investigating the other avenues. I guess I'll never know how it got lost. I apologise for causing extra trouble. Thanks for merging the threads. Perhaps doing this in the very early hours was a mistake, but I have other commitments/tasks at other times.

Regarding the external junction box, I'll try phoning to request that someone be sent to check it, and perhaps replace it with a new one with a door that shuts properly and will keep out birds, squirrels and other adventurous and hungry animals that live around here and have no respect for technology. In retrospect, I should have thought of checking it earlier.

[aaronsloman]

Apologies for leaving out power levels. I wasn't aware I had omitted anything. I'll investigate later, tonight, after catching up with other urgent tasks. Thanks.
Aaron