Hub 3.0 keeps rebooting

[zygote]

Hi, we have a Hub 3 which is randomly rebooting.  Normally happens once every few days but today it's happening multiple times per hour!!  We had the same issue a couple of months ago and the hub was swapped out, which seemed to alleviate the issue for a while, but it's back again.

Logs/config from the front end follows.  Lots of "critical No Ranging Response received - T3 time-out",  followed by "critical Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out".

Not sure if they're normal behaviour or indicative of a problem. Can anyone help?

Downstream bonded channels

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID

1 419000000 8.3 40 256 qam 36

2 235000000 8 40 256 qam 13

3 243000000 7.6 40 256 qam 14

4 251000000 7.5 40 256 qam 15

5 259000000 7.5 40 256 qam 16

6 267000000 7.3 40 256 qam 17

7 275000000 7.1 40 256 qam 18

8 283000000 7 40 256 qam 19

9 291000000 7.1 40 256 qam 20

10 299000000 7 40 256 qam 21

11 307000000 7 40 256 qam 22

12 315000000 7.5 40 256 qam 23

13 323000000 7.8 40 256 qam 24

14 331000000 7.8 40 256 qam 25

15 339000000 8 40 256 qam 26

16 347000000 7.9 40 256 qam 27

17 355000000 8 40 256 qam 28

18 363000000 8.3 40 256 qam 29

19 371000000 8.5 40 256 qam 30

20 379000000 8.4 40 256 qam 31

21 387000000 8.5 40 256 qam 32

22 395000000 8.5 40 256 qam 33

23 403000000 8.4 40 256 qam 34

24 411000000 8.5 40 256 qam 35

Downstream bonded channels

Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors

1 Locked 40.9 0 0

2 Locked 40.9 5 0

3 Locked 40.3 0 0

4 Locked 40.3 0 0

5 Locked 40.3 5 0

6 Locked 40.3 4 0

7 Locked 40.9 6 0

8 Locked 40.9 5 0

9 Locked 40.9 5 0

10 Locked 40.3 5 0

11 Locked 40.3 6 0

12 Locked 40.3 7 0

13 Locked 40.9 5 0

14 Locked 40.9 0 0

15 Locked 40.3 4 0

16 Locked 40.9 0 0

17 Locked 40.9 0 0

18 Locked 40.3 5 0

19 Locked 40.3 5 0

20 Locked 40.3 5 0

21 Locked 40.9 5 0

22 Locked 40.3 5 0

23 Locked 40.3 0 0

24 Locked 40.3 5 0

Upstream bonded channels

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID

1 53699969 56.8 5120 64 qam 2

Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1 ATDMA 0 0 0 0

General Configuration

Network access

Allowed

Maximum Number of CPEs

1

Baseline Privacy

Enabled

DOCSIS Mode

Docsis30

Config file

A,.iyewrkldJKDHSUBsgvca69834n

Primary Downstream Service Flow

SFID 3122

Max Traffic Rate 575000000

Max Traffic Burst 42600

Min Traffic Rate 0

Primary Upstream Service Flow

SFID 3121

Max Traffic Rate 38520000

Max Traffic Burst 42600

Min Traffic Rate 0

Max Concatenated Burst 16320

Scheduling Type BestEffort

Time Priority Description

25/03/2022 16:58:57 notice LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:50:25 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:49:9 critical 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;

25/03/2022 16:47:10 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:47:9 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:47:9 critical Ranging Request Retries exhausted;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:46:49 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:16:42 critical 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;

25/03/2022 16:14:26 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:13:32 notice LAN login Success;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:13:26 Warning! LAN login FAILED : Incorrect Username / Password / ConnectionType;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:12:23 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 16:11:13 critical 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;

25/03/2022 15:56:14 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 15:54:59 critical 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;

25/03/2022 15:52:59 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 15:52:59 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 15:52:59 critical Ranging Request Retries exhausted;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 15:44:57 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

25/03/2022 15:44:15 critical 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;

[Andrew-G]

You have a serious upstream noise problem, and as a result you've only got one upstream channel where there should be four, and that's operating at far too high a level.  I'll flag for staff to advise, probably needs a technician visit.

[Anonymous]

Have you checked your local service status via the website? 

[zygote]

Thanks for the reply, that’s really helpful. What would be an acceptable range, out of interest. I’m getting the upstream bandwidth I’d expect so I assume the number of channels isn’t a factor for that?

[Tudor]

You definitely need 4 upstream channels, no two ways about it.

[Andrew-G · Accepted solution]

@zygote  I’m getting the upstream bandwidth I’d expect so I assume the number of channels isn’t a factor for that?

The number of channels can drift up or down, so you might have 2, 3, 4 (even very rarely 5) much of the time.  Normally a healthy connection uses four channels all running at 64 QAM, and power levels lower than 50 dBmV.  Higher power levels show the hub is "shouting to be heard" by the network control gear.

On lower speed contracts it is possible that one or two upstream channels can provide the bandwidth, but due to the way cable internet works, upstream problems commonly disrupt synchronisation between hub and VM's network gear, leading to reliability problems more often than upstream speed problems.

[Ayisha_B]

Hi @zygote,

Welcome to our Community Forums and thanks for your post. 

I am sorry to hear your hub keeps rebooting randomly!

I've taken a look at our systems and @Andrew-G is correct, there's only one upstream channel and that is not operating at the optimal level.

At the time of writing, I can also see the downstream signal levels are out of spec.

We'll need to get a technician visit arranged so I'll pop you a PM now to confirm some details. 

Hope to hear from you soon 🙂

[Ayisha_B]

Thanks for confirming the requested details via PM @zygote,

I've booked a technician for you to come out and have a look into the issues with your service. You can find confirmation of the visit via your online account. Please let me know if there are any problems with the date or time and I can look to reschedule this for you. In regards to the appointment there are some details you need to know about. There will be no charge for this visit unless:

•The technician diagnoses the faults as not being caused by our network/equipment 
•The technician discovers that the fault or problem relates to your equipment
•The technician discovers that the fault or problem relates to any system that we are not responsible for

The technician will confirm during their visit if any of these instances apply, and if so, a £25 charge will be applied to your account.

Please ensure there is someone over the age of 18 present at the time of the visit. If you need to change or cancel your appointment you can also do this online or via the MyVM app by 4pm the day before the appointment.

If you do miss an agreed appointment for any reason, a £25 missed appointment charge will be applied to your account on the day of the appointment.

Let us know how the visit goes!

[zygote]

Hi Ayisha

Sorted now.  The fault was with the box on the wall outside where the fibre comes in.  Replaced and now and all within expected values.

Thanks for your help.

[zygote]

Thanks for your help Andrew. Fixed now. The engineer replaced the box where the fibre comes in to the house.