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longdogsuk
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No Ranging and Sync failure

Two weeks of continual dropout, resets, service status checks have led me to post here hoping somebody @ Virgin picks it up.

Continually getting failures on ranging and sync, thus lots of latency, terrible upload speeds and packet drops (oh i used to be a network engineer).

Enjoy the details in the following posts.

Also my hub has been hard reset, factory reset, cables checked, connected wired and wireless, and no obvious damage to cable (i mean it works well for a few hours a day)

longdogsuk_0-1602094551273.png

Here are the settings (which reading posts seems to indicate far too much power and the need for an engineer to pop an attenuator in or more my connection in cabinet (that's just a scan few hundred metres away).

Downstream bonded channels

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

13310000000.238256 qam25
2203000000-0.237256 qam9
32110000000.537256 qam10
42190000000.538256 qam11
52270000000.538256 qam12
62350000000.938256 qam13
72430000000.537256 qam14
8251000000037256 qam15
9259000000-0.537256 qam16
10267000000-137256 qam17
11275000000037256 qam18
122830000001.437256 qam19
132910000001.737256 qam20
142990000001.738256 qam21
153070000001.238256 qam22
163150000000.537256 qam23
173230000000.237256 qam24
183390000000.237256 qam26
193470000000.737256 qam27
20355000000137256 qam28
213630000000.738256 qam29
223710000000.938256 qam30
233790000000.937256 qam31
243870000000.237256 qam32



Downstream bonded channels

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

1Locked38.61680
2Locked37.312951843783
3Locked37.612339624869
4Locked38.61179929344
5Locked38.61060852967
6Locked38.991137588
7Locked37.685159416
8Locked37.679956405
9Locked37.672592143
10Locked37.66822050
11Locked37.6368320
12Locked37.676020
13Locked37.622610
14Locked38.611220
15Locked38.66430
16Locked37.37310
17Locked37.63950
18Locked37.6490
19Locked37.6100
20Locked37.660
21Locked38.660
22Locked38.640
23Locked37.650
24Locked37.600

 

Upstream bonded channels

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

1394000244.675512064 qam10
2257999984.525512064 qam12
3326000244.525512064 qam11
4462000024.675512064 qam9



Upstream bonded channels

Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts

1ATDMA0000
2ATDMA0000
3ATDMA0000
4ATDMA0000

 

 

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MikeRobbo
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Re: No Ranging and Sync failure

Can you post a 'Live Link' to your BQM please.

Instructions for posting BQM Link

Under your BQM graph are two links in red.

Click the lower link (Share Live Graph) then click generate.

Copy the text in the Direct Link box, beware, there may be more text than you can see.

On here click the Link icon (2 links chain to the left of the camera icon)

In the URL box paste the link you copied and in the ‘text to display’ box write My BQM then click OK - you can post the link straight away.


*********************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************
BT Smart Hub 2 with 70Mbs Download,18Mbs Upload, 9.17ms Latency & 0.35ms Jitter.
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longdogsuk
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Re: No Ranging and Sync failure

rest of details

Sample error messages from today (just as an example)

07/10/2020 16:38:28criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 16:06:34criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 16:02:12criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 15:26:36criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 15:16:36criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 14:28:18criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 14:23:1criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 14:21:23criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 14:04:4criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 13:52:51criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 13:45:45criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 13:35:12criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 13:15:28criticalNo Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
07/10/2020 13:00:29criticalSYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

 

Cable Modem StatusItem Status Comments

Acquired Downstream Channel (Hz)
331000000
Locked
Ranged Upstream Channel (Hz)
39400024
Locked
Provisioning State
Online

 

General Configuration

Network access
Allowed
Maximum Number of CPEs
1
Baseline Privacy
Enabled
DOCSIS Mode
Docsis30
Config file
69834ncxv9873254k;fg87dsfd;kfo



Primary Downstream Service Flow

SFID3280
Max Traffic Rate230000061
Max Traffic Burst42600
Min Traffic Rate0



Primary Upstream Service Flow

SFID3279
Max Traffic Rate22000061
Max Traffic Burst42600
Min Traffic Rate0
Max Concatenated Burst42600
Scheduling TypeBestEffort

 

Screen Shot 2020-10-07 at 19.14.52.jpeg

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longdogsuk
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Re: No Ranging and Sync failure

My BQM 

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Andrew-G
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Re: No Ranging and Sync failure

An attenuator won't help, as your power levels, SNR and modulation were all fine when you posted that data.  But your error counts indicate a noise problem that's pronounced from 200 MHz to 235 MHz.  What's causing that I can't say - could be a crimped coax cable anywhere on the local segment (including customer properties), noise ingress from external radio signals, or a range of other things.

This is at the heart of the RF technology that DOCSIS uses, so you'd expect VM to be able to spot that, and have the resources to track it down and fix it.  Then again, any long standing VM customer might NOT expect that.

I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more

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longdogsuk
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Re: No Ranging and Sync failure

Weirdly following the post the service has been stable for the past week.

I did nothing that i hadn't already done but now it all seems fine.

Time will tell

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