Superhub Connection Dropping.

MacmillaN · 13-07-2015, 13:42

Hello,
My Connection has been dropping for the past few days at different times of the day,
A modem reset usually brings the connection back online.
When the internet connection goes offline, the set-top boxes Online light flashes and usually drops the channel image.

The modem has just came back online.
But just wanted to check the Logs of the modem.(Superhub VMDG480)

I was not sure what logs was required, the network log was blank.

Information
Cable Modem EuroDOCSIS
Serial Number 2HA31CU70A2FB
Boot Code Version 2.3.0beta7
Software Version V2.39.02
Hardware Version 2.00
CA Key Installed

Cable Modem StatusItem Status Comments
Acquired Downstream Channel (Hz) 299000000 Hz Locked
Ranged Upstream Channel (Hz) 23600000 Hz Success
Provisioning State OK Operational

Downstream DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8299000000 Hz 267000000 Hz 275000000 Hz 283000000 Hz 291000000 Hz 307000000 Hz 315000000 Hz 323000000 HzLocked Locked Locked Locked Locked Locked Locked Locked21 17 18 19 20 22 23 24QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM2566.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17-4.7 dBmV -6.0 dBmV -8.4 dBmV -6.9 dBmV -6.1 dBmV -5.0 dBmV -5.4 dBmV -5.7 dBmV37.4 dB 36.8 dB 36.0 dB 36.8 dB 37.2 dB 37.4 dB 37.2 dB36.8 dB

Downstream DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8299000000 Hz 267000000 Hz 275000000 Hz 283000000 Hz 291000000 Hz 307000000 Hz 315000000 Hz 323000000 HzLocked Locked Locked Locked Locked Locked Locked Locked21 17 18 19 20 22 23 24QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM2566.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17 I=12J=17-4.7 dBmV -6.0 dBmV -8.4 dBmV -6.9 dBmV -6.1 dBmV -5.0 dBmV -5.4 dBmV -5.7 dBmV37.4 dB 36.8 dB 36.0 dB 36.8 dB 37.2 dB 37.4 dB 37.2 dB 36.8 dB

Upstream Burst Req(1) Init Maint(3) Per Maint(4) Adv Short(9) Adv Long(10) Adv UGS(11)QPSK QPSK QPSK 16QAM 16QAM 16QAMOff Off Off Off Off Off56 384 384 96 104 104396 6 6 1028 1028 10280 0 0 6 8 816 34 34 150 236 2360 0 0 3 0 08 48 48 8 8 8Fixed Fixed Fixed Short Short ShortOn On On On On On

General Configuration
Network Access Allowed
Maximum Number of CPEs 1
Baseline Privacy Enabled
DOCSIS Mode EU DOCSIS 3.0
Config File

Primary Downstream Service Flow
SFID 23892
Max Traffic Rate 133000000 bps
Max Traffic Burst 16320 bytes
Min Traffic Rate 6650000 bps
Primary Upstream Service Flow
SFID 23891
Max Traffic Rate 12000000 bps
Max Traffic Burst 16320 bytes
Min Traffic Rate 0 bps
Max Concatenated Burst 16320 bps
Scheduling Type BestEffort

Many thanks for your help!

General Maximus · 13-07-2015, 20:50

at face value I would say your downstream power is too low, it definitely doesn't want to be -8. You copied the info from the wrong upstream tab. Can you copy "upstream" and not upstream burst. It will be a table with four columns, one for each channel and will look something like this

MacmillaN · 14-07-2015, 05:54

Upstream
US-1 US-2 US-3 US-4
Channel Type 2.0 2.0 N/A N/A
Channel ID 41 42 N/A N/A
Frequency (Hz) 23600000 Hz 30200000 Hz N/A N/A
Ranging Status Success Success N/A N/A
Modulation QAM16 QAM16 N/A N/A
Symbol Rate (Sym/sec) 5120000 5120000 N/A N/A
Mini-Slot Size 128 128 N/A N/A
Power Level (dBmV) 52.8 dBmV 54.0 dBmV N/A N/A
T1 Timeouts 0 0 N/A N/A
T2 Timeouts 0 0 N/A N/A
T3 Timeouts 0 0 N/A N/A
T4 Timeouts 0 0 N/A N/A

arcimedes · 14-07-2015, 08:54

Yes upstream power is high, suggest you contact VM

MacmillaN · 15-07-2015, 03:04

Quote:

Originally Posted by arcimedes

Yes upstream power is high, suggest you contact VM

Thanks for your Reply arcimedes.
Would the Power level-sort themselves out? Wondering the the Power Levels would sort themselves out before the Engineer arrived, which would make that a pointless visit by a VM engineer (What should the power levels be normally and what would be the reason for the sudden change to them?)
(Would this also me the cause for the TIVO and V+ channel drops and on-demand light flashing exactly at the same-time as the internet connection is lost?)

I did contact VM:-

VM stated that there appears to be some problems with both the upstream and downstream power levels. Engineer booked for early next week!

Do you have any idea, what the engineer would do to bring down or increase the Power Levels?
Just wondering the above information. Maybe i am thinking too much about this!

General Maximus · 15-07-2015, 10:19

You have done the right thing and what I was going to suggest. Your power levels coincide with your distance from your street cabinet and it is all to do with having just the right amount of power for your "signal" to get back and forth. As we can see, it is possible to either have too much or too little. In the cabinet you are connected to a "tap point". Not all tap points are equal and they have varying degrees of power going into them so people further from the street cabinet get more power to push the signal along and people closer to the cabinet get less. When the tech comes round he'll move your tap point so you get less downstream power.

Before he goes make sure you check your power levels and that he has fixed the problem. Your downstream wants to be as close to 0 as possible but anything from -3 to +4 is very good. Your upstream wants to be below 50 and anything around 45 is also very good. Long story short, if they are anything like the screen dumps in the other thread, you can be very happy.

MacmillaN · 22-07-2015, 16:10

Engineer visit has just taken place. (He changed some Splitters and added a signal optimization powered box?)

Here are the New Downstream/Upstream Logs

Downstream
DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 299000000 Hz 267000000 Hz 275000000 Hz 283000000 Hz 291000000 Hz 307000000 Hz 315000000 Hz 323000000 Hz
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 21 17 18 19 20 22 23 24
Modulation QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256
Symbol Rate (Msym/sec) 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level (dBmV) -1.3 dBmV -1.7 dBmV -1.8 dBmV -1.9 dBmV -2.4 dBmV -1.4 dBmV -1.7 dBmV -1.9 dBmV
RxMER (dB) 37.8 dB 37.5 dB 37.8 dB 37.8 dB 37.8 dB 37.5 dB 37.5 dB 37.1 dB

Upstream
US-1 US-2 US-3 US-4
Channel Type 2.0 2.0 N/A N/A
Channel ID 42 41 N/A N/A
Frequency (Hz) 30200000 Hz 23600000 Hz N/A N/A
Ranging Status Success Success N/A N/A
Modulation QAM16 QAM16 N/A N/A
Symbol Rate (Sym/sec) 5120000 5120000 N/A N/A
Mini-Slot Size 128 128 N/A N/A
Power Level (dBmV) 49.3 dBmV 49.8 dBmV N/A N/A
T1 Timeouts 0 0 N/A N/A
T2 Timeouts 0 0 N/A N/A
T3 Timeouts 1 1 N/A N/A
T4 Timeouts 0 0 N/A N/A

General Maximus · 22-07-2015, 16:31

they are a lot better and well within spec now

MacmillaN · 22-07-2015, 19:32

Checked just a minute ago and Upstream has gone back up?
Downsteam appears to be very similar to my first report after tech visit.

Upstream
US-1 US-2 US-3 US-4
Channel Type 2.0 2.0 N/A N/A
Channel ID 42 41 N/A N/A
Frequency (Hz) 30200000 Hz 23600000 Hz N/A N/A
Ranging Status Success Success N/A N/A
Modulation QAM16 QAM16 N/A N/A
Symbol Rate (Sym/sec) 5120000 5120000 N/A N/A
Mini-Slot Size 128 128 N/A N/A
Power Level (dBmV) 52.3 dBmV 50.8 dBmV N/A N/A
T1 Timeouts 0 0 N/A N/A
T2 Timeouts 0 0 N/A N/A
T3 Timeouts 1 1 N/A N/A
T4 Timeouts 0 0

Downstream
DS-1 DS-2 DS-3 DS-4 DS-5 DS-6 DS-7 DS-8
Frequency (Hz) 299000000 Hz 267000000 Hz 275000000 Hz 283000000 Hz 291000000 Hz 307000000 Hz 315000000 Hz 323000000 Hz
Lock Status(QAM Lock/FEC Sync/MPEG Lock) Locked Locked Locked Locked Locked Locked Locked Locked
Channel ID 21 17 18 19 20 22 23 24
Modulation QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256
Symbol Rate (Msym/sec) 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000 6.952000
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17 I=12
J=17
Power Level (dBmV) -1.4 dBmV -1.8 dBmV -1.8 dBmV -2.0 dBmV -2.6 dBmV -1.4 dBmV -2.3 dBmV -2.5 dBmV
RxMER (dB) 37.8 dB 37.5 dB 38.0 dB 37.9 dB 37.8 dB 37.7 dB 37.5 dB 37.2 dB

arcimedes · 22-07-2015, 21:03

Are you getting any problems?

MacmillaN · 22-07-2015, 22:31

Quote:

Originally Posted by arcimedes

Are you getting any problems?

Well no problems as yet, but General_Maximus above stated that the upstream level should be below 50 and anything around 45 is also very good.

horseman · 23-07-2015, 05:09

Quote:

Originally Posted by MacmillaN

Well no problems as yet, but General_Maximus above stated that the upstream level should be below 50 and anything around 45 is also very good.

That's because it depends on the modulation type and therefore allow 3dB safety margin for highest(64QAM) level at 51dBmv.
16QAM can potentially tolerate 52.2dBmv

So allowing for diurnal ambient temperature variances then in current hot weather periods anything higher than 48dBmv could potentially start causing issues if they rise further with diurnal creep along with the reduction in D/S power potentially dropping below -6dBmv on 256QAM

Best really to post on VM forum so they can check on upstream T3/SNR/FEC-RS counts as levels on 1 channel appear uncomfortably borderline and if 64QAM is being rolled out in your area they will probably break anyway!

MacmillaN · 23-07-2015, 20:30

Quote:

Originally Posted by horseman

That's because it depends on the modulation type and therefore allow 3dB safety margin for highest(64QAM) level at 51dBmv.
16QAM can potentially tolerate 52.2dBmv

So allowing for diurnal ambient temperature variances then in current hot weather periods anything higher than 48dBmv could potentially start causing issues if they rise further with diurnal creep along with the reduction in D/S power potentially dropping below -6dBmv on 256QAM

Best really to post on VM forum so they can check on upstream T3/SNR/FEC-RS counts as levels on 1 channel appear uncomfortably borderline and if 64QAM is being rolled out in your area they will probably break anyway!

Thanks for your advice, I posted on the VM community forum. Currently waiting on someone to get back to me regarding the upstream power levels.

General Maximus · 24-07-2015, 09:31

Quote:

Originally Posted by horseman

So allowing for diurnal ambient temperature variances then in current hot weather periods anything higher than 48dBmv could potentially start causing issues if they rise further with diurnal creep along with the reduction in D/S power potentially dropping below -6dBmv on 256QAM

That is exactly what I was thinking, I was accounting for diurnal temperature variances

horseman · 25-07-2015, 14:23

Quote:

Originally Posted by General Maximus

That is exactly what I was thinking, I was accounting for diurnal temperature variances

Naturally you particularly have to watch the haemorrhoids at your age at this time of year when sitting on too many street cabinets in the sunshine....