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GreenReaper
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Chewed external cable, high upstream power, resets every midnight

This year we returned with a new TV+M350+Phone Oomph bundle starting January 4. However I think we'll need help to make this contract work, especially now animals have been chewing the cable.

The QuickStart pack worked fine, to start with. However ~0-45 minutes after midnight the Hub regularly resets the cable interface, dropping us all off both wired and wireless connections. I've seen this reported in many other threads within the last year, but not with our other issues.

Combined with this, there appears to be an upstream power issue, particularly in the lower bands, resulting in T3 timeouts on most channels; 25.8Mhz is by far the worst of them.

After a reset they all move to 51dBmV power almost immediately and would go higher if they could. After reboot with one channel connected it hit 55dBmV. Often it returns with TCS partial service (three channels) for hours. When the lowest upstream channel does come back, it can get stuck on 32qam.

Downstream signal is also marginal - a few channels have hundreds or thousands of Pre RS Errors, again in the lower channels 2-8 (138-163Mhz) where RxMER (dB) has fallen below 36. Channels 2-5 are worst.

When it does work, I get full speed from the service - which is good, because we paid extra to upgrade that, and make good use of it, as shown below. The big issue is the midnight resets, which come at a busy time for us.

Looking outside, I found that animals - probably foxes, who have a den next door - chewed the exterior cables coming up the side of our drive and broke its sheath. I don't know if this causes our issues, but it probably doesn't help, and I worry it might cause noise for others. Don't really have the equipment to fix it!

Chewed cable w/ metal showingChewed cable w/ metal showing

They dented the pipe, tooThey dented the pipe, too

These cables subsequently enter an omnibox outside the front of the property and the main cable enters a 3.6dB passive splitter. One line goes to the back of the house where we previously had the TV box, while the other (and the old Virgin phone line) enters by the front door.

There is then a ~3m run of white cable extending from the front door socket, installed by a Virgin engineer when we had service with a separate phone line, and split with the new combined splitter to the Hub and the TV box. Connecting the Hub directly to the socket did not significantly alter the upstream power issues or fix the resets.

Previously our SuperHub 2ac was connected directly via the extension cable and the TV box was on a second line at the back of the house. This line still works, but is 3dB quieter. At that time downstream signal was so high the engineer fitted a 6db purple forward path attenuator (marked A1823/05R) to the 2ac. It's not on the Hub 3 because downstream levels are already ~0dB after the internal Hub/TV splitter. (I tried anyway, but it did not stop it resetting.)

The downtime is visible as a gap on my microserver's network graphs (time is CEST, so 01:00 is midnight).

Outage at midnight (01:00)Outage at midnight (01:00)

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GreenReaper
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Re: Chewed external cable, high upstream power, resets every midnight

Upstream bonded channels

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

13940016151512064 qam2
23260000051512064 qam3
34620000051512064 qam1
42580000051512032 qam4

 

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1ATDMA0000
2ATDMA0010
3ATDMA0010
4ATDMA00600

 

Downstream bonded channels

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

1202750000036256 qam9
2138750000-1.235256 qam1
3146750000-0.535256 qam2
4154750000-0.235256 qam3
5162750000035256 qam4
6170750000-0.436256 qam5
7178750000-1.235256 qam6
8186750000-0.935256 qam7
9194750000-0.436256 qam8
10210750000036256 qam10
11218750000036256 qam11
12226750000036256 qam12
132347500000.236256 qam13
142427500000.236256 qam14
15250750000-0.236256 qam15
16258750000-0.236256 qam16
172667500000.236256 qam17
182747500000.536256 qam18
19282750000136256 qam19
202907500001.537256 qam20
212987500001.537256 qam21
223067500001.436256 qam22
233147500001.237256 qam23
243227500001.236256 qam24
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GreenReaper
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Re: Chewed external cable, high upstream power, resets every midnight

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

1Locked36.3190
2Locked3513640
3Locked35.53570
4Locked35.54480
5Locked35.54110
6Locked36.3370
7Locked35.7440
8Locked35.7900
9Locked36.3350
10Locked36.3250
11Locked36.6130
12Locked36.6120
13Locked36.3200
14Locked36.3240
15Locked36.3150
16Locked36.3200
17Locked36.3200
18Locked36.6130
19Locked36.370
20Locked37.390
21Locked37.3280
22Locked36.6120
23Locked37.3230
24Locked36.6120

 

General Configuration

Network access
Allowed
Maximum Number of CPEs
1
Baseline Privacy
Enabled
DOCSIS Mode
Docsis30
Config file
cmreg-vmdg505-bbt062+voc-b.cm

Primary Downstream Service Flow

SFID33474
Max Traffic Rate402500089
Max Traffic Burst42600
Min Traffic Rate0

Primary Upstream Service Flow

SFID33473
Max Traffic Rate38500089
Max Traffic Burst42600
Min Traffic Rate0
Max Concatenated Burst42600
Scheduling TypeBestEffort

 

Network Log

24/01/2021 00:36:39criticalNo Ranging Response received - T3 time-out;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
24/01/2021 00:36:3noticeLAN login Success;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
24/01/2021 00:35:58criticalNo Ranging Response received - T3 time-out;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
24/01/2021 00:12:43Warning!TCS Partial Service;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
24/01/2021 00:12:43Warning!Initializing Channel Timeout Expires - Time the CM can perform initial ranging on all upstream channels in the TCS has expired;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
23/01/2021 22:08:58criticalNo Ranging Response received - T3 time-out;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
23/01/2021 18:29:38noticeLAN login Success;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
23/01/2021 06:23:39criticalNo Ranging Response received - T3 time-out;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
23/01/2021 00:22:15noticeLAN login Success;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
23/01/2021 00:00:40criticalNo Ranging Response received - T3 time-out;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 21:09:13noticeLAN login Success;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 21:08:59Warning!LAN login FAILED : Incorrect Username / Password / ConnectionType;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 18:13:54noticeLAN login Success;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 07:05:57criticalNo Ranging Response received - T3 time-out;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 05:18:18Warning!TCS Partial Service;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 05:18:17Warning!Initializing Channel Timeout Expires - Time the CM can perform initial ranging on all upstream channels in the TCS has expired;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 05:18:3criticalNo Ranging Response received - T3 time-out;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 04:00:34noticeLAN login Success;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 01:44:21Warning!TCS Partial Service;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
22/01/2021 01:44:20Warning!Initializing Channel Timeout Expires - Time the CM can perform initial ranging on all upstream channels in the TCS has expired;CM-MAC=[cut];CMTS-MAC=[cut];CM-QOS=1.1;CM-VER=3.0;
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GreenReaper
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Re: Chewed external cable, high upstream power, resets every midnight

Forgot to mention: the unused line is capped at the socket. I should also note that the downstream difference varies over time, as do the channels. For example, this was the state just twenty minutes ago:

Downstream bonded channels

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

1202750000036256 qam9
2138750000-135256 qam1
3146750000-0.235256 qam2
4154750000035256 qam3
5162750000035256 qam4
6170750000-0.236256 qam5
7178750000-0.935256 qam6
8186750000-0.735256 qam7
9194750000-0.236256 qam8
102107500000.236256 qam10
11218750000036256 qam11
12226750000036256 qam12
132347500000.436256 qam13
142427500000.536256 qam14
15250750000036256 qam15
16258750000036256 qam16
172667500000.436256 qam17
182747500000.736256 qam18
192827500001.436256 qam19
202907500001.737256 qam20
212987500001.937256 qam21
223067500001.537256 qam22
233147500001.437256 qam23
243227500001.436256 qam24

 

Ten minutes after these readings the interface reset, dropping all connections as usual. When service resumed ten minutes later, a new set of downstream frequencies were in use, all of which were above 200Mhz (switching out all 8 lower channels), none of which now had <0 dBmV:

Downstream bonded channels

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

1202750000036256 qam9
22107500000.236256 qam10
3218750000036256 qam11
4226750000036256 qam12
52347500000.436256 qam13
62427500000.536256 qam14
7250750000036256 qam15
8258750000036256 qam16
92667500000.436256 qam17
102747500000.737256 qam18
112827500001.436256 qam19
122907500001.937256 qam20
132987500001.937256 qam21
143067500001.737256 qam22
153147500001.537256 qam23
163227500001.436256 qam24
173307500001.237256 qam25
183707500000.737256 qam26
193787500000.737256 qam27
203867500000.237256 qam28
21394750000037256 qam29
22402750000037256 qam30
23410750000037256 qam31
24418750000037256 qam32

 

The log shows the following changes (the T3 timeouts were again registered on 25.8MHz):

Time Priority Description

25/01/2021 00:26:22criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
25/01/2021 00:25:45Warning!TCS Partial Service;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
25/01/2021 00:25:45Warning!Initializing Channel Timeout Expires - Time the CM can perform initial ranging on all upstream channels in the TCS has expired;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
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jbrennand
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Re: Chewed external cable, high upstream power, resets every midnight

Yep looks like an Upstream issue - too many T3's an the power levels all at the top of the range and qam dropping. The chewed cable may be the source of the issue - but it needs VM to take a look at your connection in more detail.

Call it in and report it - try at 08.00 for the best chance of getting through quickly.

Also, in the meantime... if you haven’t already, set up a free and secure “Broadband Quality Monitor” to continually monitor the state of your connection and record any true network dropouts , latency issues, packet drops, etc - it will thus allow you to differentiate between those and simple wifi dropouts. It does it 24/7/365 and it keeps a visual record of any/all of your network disconnections, useful data to have to match to the Network logs (in your Hub settings) and also in discussions with VM - as this is the "measure" they prefer to look at.

Post up the “link” to the “share live graph” (as per instructions on the TB website) when it starts to develop.

https://www.thinkbroadband.com/broadband/monitoring/quality


--------------------
John
--------------------

I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.
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GreenReaper
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Re: Chewed external cable, high upstream power, resets every midnight

Thanks for the reply. I have made a BQM. I doubt it will show much because downtime, while annoying, is only ~5-10min, but we'll see. To an extent, ping variation is expected given upstream usage (avg. ~8-9Mbps, as the net graph linked earlier shows, but bursting to ~18-37Mbps).

My Broadband Ping - Virgin Home

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-tony-
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Re: Chewed external cable, high upstream power, resets every midnight

you have done the diagnosis - whether its the cable or not it needs sorting as the 1st step - ring it in - keep it simple you will confuse the hell out of them if you get offshore - just say its faulty and drops - they may want to charge you £99 if you start talking about damaged cables so dont go down that path - keep the detail for the tech - they can repair the cable but given the damage it could need a re pull

____________________

Tony
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