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-   -   100M : Hub reboots by itself (https://www.cableforum.uk/board/showthread.php?t=33711068)

Newusercrook 25-05-2022 00:12

Hub reboots by itself
 
Hi, Have been having problems for over two months now with our hub3 reseting. Seems to have some favourite times to reset, early morning, mid afternoon and late evening, but can be anytime. Tech guys have changed everything in the house and tried using the next door neighbours cable but still the same. They are baffled, we think there something wrong in the cabinet, or a network setting somewhere. Completely exhausted and stressed out. Any ideas?

InsaneNutter 26-05-2022 09:56

Re: Hub reboots by itself
 
Historically the older Hubs used to crash quite frequently, unless they were in modem mode. I don't know if that's still the case as mine have never not been in modem mode, however it wouldn't hurt putting it in modem mode, connecting up your own router and seeing it the Hub 3 continues to reboot or not.

Newusercrook 26-05-2022 21:29

Re: Hub reboots by itself
 
Ok interesting.. I'm mean we've had the same hub type for years but only started having problems in the last 2-3 months. I've only read about modem mode, never used it. Do you have a recommendation for a router?

Sephiroth 28-05-2022 09:36

Re: Hub reboots by itself
 

The Hub 3 is a well behaved device in my experience. The usual reason for frequent self resets is what is known as a T4 Timeout, when the VM side has made 16 unsuccessful attempts to get a response to its keep-alive signal.

Evidence for this would be found in the Network Log and in the power stats; if the upstream power is very high (in the 50 range) then we can advise you from there. If the downstream power is in deep negative territory, then ditto.

First thing always to check is that the coaxial cable is firmly screwed in both ends.


Newusercrook 29-05-2022 20:50

Re: Hub reboots by itself
 
Hi,
upstream 44 to 46, downstream -4.7 to -7, T4 not recently, there has been T3 as below but nothing logged since 27th - despite rebooting on 28 and 29th.

This has been going on for months.. We've had new hubs, new cables, used next door neighbours road cable, installed UPS, techn guy visits - but no success..!


27/05/2022 17:30:21 Warning! RCS Partial Service
27/05/2022 17:30:21 critical SYNC Timing Synchronization failure - Loss of Sync;
27/05/2022 17:30:20 Warning! RCS Partial Service;
26/05/2022 17:46:18 critical No Ranging Response received - T3 time-out;

Sephiroth 29-05-2022 22:14

Re: Hub reboots by itself
 
The RCS message & loss of sync suggests a downstream problem.

Are you able to copy and paste the stats? I'd be looking for poor SNR? If some channels have poor signal, then packets will be corrupted.


Newusercrook 30-05-2022 21:23

Re: Hub reboots by itself
 
Not sure what classifies as poor but stats are below, although if it's only poor at the time of loss it's difficult to capture. To be honest the router log doesn't tie up with when the reboots occur, unless for some reason it doesn't log the reboot events. Virgin say they have monitored the connection, but initially could only see a slope on the signals. Recently they say they can see it dropping, but don't seem to have any idea why..

1 515000000 -6.7 38 256 qam 48
2 331000000 -4.2 38 256 qam 25
3 339000000 -4.2 38 256 qam 26
4 347000000 -4.2 40 256 qam 27
5 355000000 -4.4 38 256 qam 28
6 363000000 -4.4 40 256 qam 29
7 371000000 -4.4 38 256 qam 30
8 379000000 -4.5 38 256 qam 31
9 387000000 -4.7 40 256 qam 32
10 395000000 -4.9 40 256 qam 33
11 403000000 -4.9 38 256 qam 34
12 411000000 -5 38 256 qam 35
13 419000000 -5 38 256 qam 36
14 427000000 -5.2 38 256 qam 37
15 435000000 -5.5 38 256 qam 38
16 443000000 -5.5 38 256 qam 39
17 451000000 -6.2 38 256 qam 40
18 459000000 -6.5 38 256 qam 41
19 467000000 -6.5 38 256 qam 42
20 475000000 -6.7 38 256 qam 43
21 483000000 -6.7 38 256 qam 44
22 491000000 -6.5 38 256 qam 45
23 499000000 -6.7 38 256 qam 46
24 507000000 -6.7 38 256 qam 47


Downstream bonded channels
Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors
1 Locked 37.6 6 0
2 Locked 38.9 6 0
3 Locked 38.9 5 0
4 Locked 38.9 4 0
5 Locked 38.9 8 0
6 Locked 38.9 7 0
7 Locked 38.6 4 0
8 Locked 38.9 5 0
9 Locked 38.9 5 0
10 Locked 38.9 19 0
11 Locked 38.6 20 0
12 Locked 38.9 6 0
13 Locked 38.9 5 0
14 Locked 38.6 7 0
15 Locked 38.9 6 0
16 Locked 38.9 5 0
17 Locked 38.9 6 0
18 Locked 37.6 9 0
19 Locked 38.6 19 0
20 Locked 38.6 5 0
21 Locked 38.9 4 0
22 Locked 38.2 17 0
23 Locked 38.6 1 0
24 Locked 38.9 7 0
In theory this is a link to a BQM plot where a reboot occurs..
https://www.thinkbroadband.com/broad...437-29-05-2022

Thanks for taking an interest!

Sephiroth 30-05-2022 21:40

Re: Hub reboots by itself
 
[COLOR="Blue"]
Thanks for taking the trouble.

The "slope" that VM mentioned is the power attenuation that worsens as the frequency rises. This is evident in your pasted stats.

The SNR (labelled RxMER in the stats) is the signal to noise ratio and, to my surprise is reported as pretty much nominal.

The BQM is also perfect; no red areas across the top. No mass of high rising yellow. So over-utilisation in your area is not evident.

A couple more questions:

1. How far is your house from the VM street box that serves you? Is it verging on the 200m?

2. Is there an attenuator attached to your modem cable? If so, try removing it and see if that improves. I would not be happy with your power levels, although they are within the DOCSIS spec range.

3. Please also paste your upstream levels.

Newusercrook 31-05-2022 22:30

Re: Hub reboots by itself
 
Thanks again..

Distance.. I'd need to check, it's not close, but not 200M I think. Maybe 100M.
No attenuator.

VM say the lights on the box indicate a power disconnect or a command sent to rest the hub. Power has been ruled out as the hub has been connected to a UPS. Command ruled out by using a hub on a different account. For me the lights must mean there's something else that can cause the reset, but they don't seem to know what...

We've had the connection for years, only in the last 2-3 months has there been an issue..

Upstream
1 39399974 44.8 5120 64 qam 10
2 25799986 44.8 5120 64 qam 12
3 32599991 44.8 5120 64 qam 11
4 46200014 46.3 5120 64 qam 9

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

Sephiroth 01-06-2022 09:16

Re: Hub reboots by itself
 

Upstream is fine.

Your reply leaves little remaining. If you are still tapping off the neighbour, that would explain the low downstream power levels, but the stats don't show any poor SNR or corrupted data.

If 100m distance, your downstream power shouldn't be that low. Your neighbour's stats might be useful in diagnosis.

If it stumps them, then it looks like I'm gonna be stumped too.

That leaves the cabinet tap point or something wrong with your cable to the drop point outside your house. The latter is usually resolved by a cable re-pull; the former is usually resolved by moving you to a different tap point. However, they already did the tap point thing by piggy-back off your neighbour..


Newusercrook 13-06-2022 23:39

Re: Hub reboots by itself
 
quick update.. gone back to our own cable now as the neighbours was no better. Have also swapped over to hub4.. Waiting to see how it goes!


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