One for the Digital Care Team

[#1]

Over the last 4 days, my line has started to show signs of unsolicited loss of sync on VDSL.  On all occasions the disturbances arrived suddenly, with no previous sign of problems (such as increased error rates), and then just as suddenly disappear, and the line returns to normal.  On occasion LOS has been reported.  While this happened during 'the working week', I was of the view that perhaps it was inadvertantly occasioned by work on the D-side cabinets, but it's happened again today - maybe they're working overtime?! 
Anyway, I think this is an early sign of trouble ahead, which may result in a hard fail.  The voice Quiet Line Test is silent.
Here are a list of the resyncs over the past 4 days:
25/07/2014 08:05 - RESYNC detected (DS 78795 Kbps, US 19999 Kbps), AS = 716, Retrain Reason: 0
12/08/2014 16:33 - RESYNC detected (DS 78562 Kbps, US 19999 Kbps), AS = 36, Retrain Reason: 1
14/08/2014 13:50 - RESYNC detected (DS 60623 Kbps, US 19999 Kbps), AS = 2, Retrain Reason: 1
14/08/2014 14:09 - RESYNC detected (DS 78537 Kbps, US 19999 Kbps), AS = 33, Retrain Reason: 1
15/08/2014 10:41 - RESYNC detected (DS 77841 Kbps, US 19999 Kbps), AS = 9, Retrain Reason: 1
15/08/2014 14:29 - RESYNC detected (DS 78099 Kbps, US 19999 Kbps), AS = 3, Retrain Reason: 1
15/08/2014 15:30 - RESYNC detected (DS 78306 Kbps, US 19999 Kbps), AS = 18, Retrain Reason: 1
16/08/2014 12:12 - RESYNC detected (DS 73860 Kbps, US 19999 Kbps), AS = 53, Retrain Reason: 1
16/08/2014 12:17 - RESYNC detected (DS 78280 Kbps, US 19999 Kbps), AS = 56, Retrain Reason: 1
Nb Reason=0 is power on again after return from holiday; Reason=1 are generally DSLAM initiated (though here, not an overnight intervention by DLM)
Attached are a snapshot of all relevant modem statistics over the last 4 days, and a snapshot of the state of the line at the last resync about 2 hours ago.
Note the instantaneous losses of all SNRm at the times of each event.
Can someone run the basic line tests please & report?
Thank you.

[#2]

as there probably won't be anyone here until Monday I suggest raising a fault here https://faults.plus.net

[#3]

Hi crowroad,
I'm sorry to hear that you've been seeing issues with the connection of late however I see you've raised a fault with us, Unfortunately it seems that you haven't answered all the questions which means we cannot progress the testing. If you could view the ticket here and complete the questions we'll run the further diagnostic tests for you.

[#4]

Hi Adam,
For some reason I didn't get the email that you'd updated the thread, so the ticket has now expired.
However, there is now audible noise on the phone line - I've now heard it on several phone calls, and also on the voice QLN tests.  So, I think I need to raise a voice fault (not broadband).  How do I go about that?

[#5]

https://www.plus.net/wizard/?p=wizard&page=22965&wizard_id=38

[#6]

Thank you Jim.
Voice fault now logged.

[#7]

Hi again crowroad,
Thanks for raising this and thanks to Jim for the link!
Let us know how this goes and if you need something more 

[#8]

If you look it up on Kitz & ThinkBroadband, it's general consensus that retrain reason 1 is DLM intervention.
If your cabinet is getting more full, then it's possible crosstalk is causing problems.

[#9]

Quote from: Xreyuk

If you look it up on Kitz & ThinkBroadband, it's general consensus that retrain reason 1 is DLM intervention. If your cabinet is getting more full, then it's possible crosstalk is causing problems.

Thank you for that thought, but reason 1 does not always mean DLM intervention, particularly since the last OR firmware update.
So, sorry to disappoint you, but these resyncs have nothing to do with the crosstalk bogey man, but are caused by a loss of signal which occurs (amongst other reasons) when the SNRm reaches zero (or even negative), because of audible noise in the voice band. 
When there's more noise than signal, not even the best recovery techniques can hold sync for long in those circumstances.

[#10]

Quote from: Adam

Let us know how this goes and if you need something more

Hi Adam,
There have now been 12 disconnections in the last 9 days (inclusive), giving an average time between incidents of ~ 18hrs.  Consequently when your colleagues ran their initial line tests they found no fault.  Unsurprising.  Such is the nature of intermittent faults.  However, as I've heard the noise on the phone myself on several occasions now, there is no doubt that there is a problem.
But since I am not at all willing to give OR £99 for turning up in the quiet periods between incidents and saying there can't hear anything (I can establish that myself for free by dialing 17070,2 at anytime), I guess we shall just have to wait until the line degrades even more.