Erratic U/S SNRM and resulting DLM interventions

[#1]

Since the change of router, but unfortunately with no calls to see if they cause problems, here are my RSL plots to date. I have removed a few where the trace is steady. First 6:

[#2]

2nd six:

Notice the instability, especially on the u/s trace from around 1710 Sunday, and the drops to below 0.

[#3]

As a point of interest, although it can occasionally give duff readings, here is my JDAST log:-

[#4]

Results of an incoming call this morning. Lost connection, but it came back OK with no change in d/s noise margin, but an increase in the u/s plot. NOTE: there was no noise on the line during the change, whereas previously this had caused a burst of crackling.

[#5]

RSL plot missing from last post, and afurther one following a later incoming call

[#6]

Hi @jab1,

Thank you for letting us know that you've received the new the new router and for sending over the graphs to illustrate how your connection is looking from your side at the moment. For reference, here's a copy of your RADIUS log and today's GEA test result:

xDSL Status Check
Circuit ID:	CBUKXXXXXXXXX	Service ID:	BBEUXXXXXXXXX
Telephone NO.:	NA	Test Executed On:	11-02-2019 15:24:49

xDSL Status Test Summary
Sync Status:		Circuit In Sync
General Information
NTE Status:		NTE Power Status:	Unknown	Bypass Status:

	Upstream DSL Link Information	Downstream DSL Link Information
Loop Loss:	16.0	32.5
SNR Margin:	6.9	6.3
Errored Seconds:	0	1
HEC Errors:	0
Cell Count:	709	1091
Speed:	780	12116

Maximum Stable Rate (KBPS):	11360	Fault Threshold Rate (KBPS):	9088
Mean Time Between Retrains (Seconds):	21548	Mean Time Between Errors Upstream (Seconds):	2873
Indicative Line Quality:	A	Mean Time Between Errors Downstream (Seconds):	361
Custom Thresholds
MTBR_RED:	MTBE_RED:
MTBR_GREEN:	MTBE_GREEN:

As our tests aren't picking up the cause of the issue from here, we'll need to raise this to our suppliers and potentially book an engineer visit so that this can be investigated further. Please report the issue here and let us know when you've completed it.

[#7]

@EmilyD Thanks for the RADIUS log & GEA test. Sad to report that after a promising 36 hours, at 1840 tonight, DLM kicked in again, and raised the d/s SNR to 14dB, dropping my connection speed to 7959Kbps

I'm away from home tomorrow and a bit busy tonight so will raise a BB fault on Wednesday.

[#8]

@Gandalf, @RandallFlagg, @Gandalf.

Having done everything possible from my side, but still not resolved the issue, I have just tried to raise a BB fault, answered all the questions asked - truthfully - and your troubleshooter decided everything was OK, so auto-closed the ticket.

Any ideas what I need to do now? My connection has gone back to being erratic, and the last but one DLM change resulted in a d/s SNR of 3 - totally useless!

Current situation is a d/s SNR of 13.5dB, u/s SNR of 6.3dB and a connection speed of 9.063Mb/s

[#9]

Hi @jab1 

The pains of being truthful hey? 

Any ideas which question made the troubleshooter decide that? 

I can certainly see that there is something not quite right...

Can you possibly please try it once more for us and let us know if it works this time? 

Thanks, 

MoR

[#10]

@MasterOfReality I can't say which of my truthful answers gave rise to that obviously wrong answer, but all I can say is that at no point did i say everything was fixed, but I think I got to the end of the troubleshooter.

I'll have another go sometime tomorrow, and take careful note of the last question I am asked.

FWIW, I still think the problem  is in the BT/OR network, as DLM keeps on insisting on setting an unsustainable 3dB d/s margin, even though I am supposedly on a custom set 6dB minimum.

[#11]

@MasterOfReality Changed an answer, can't remember which, and a fault has been raised. As everything my side of the master socket has been changed, I am convinced the problem is BT's side.

As a point of interest, your line test has resulted in my connection speed rising to 13365Kbps, and the d/s SNR falling to 3.3dB which I know will result in another re-sync sometime today, as my line is too long for such a low margin, as I have been advised previously by BT engineers.

I thought the minimum had been custom set to 6dB?

[#12]

As a picture paints a thousand words (as they say), just thought I'd post my RSL plots from today:

[#13]

Hi @jab1, thanks for your post.

I've run line diagnostics and we are showing that you're currently set to 6dB.

I'm slightly concerned that on checking our connection logs I'm now not seeing an ongoing connection, with it cutting out at around 13:08 this afternoon.

Can you confirm what you're seeing your end?

[#14]

@OskarPapa - yup, it did exactly that at 13.08, and again at 13.49 - see the RSL plots in the post above yours.

As you can see from those, I had a definite 3.3dB margin at that point, then it shot up to around 14.8dB, and down to around 6dB after the re-sync at 13.49.

NONE of this is anything changing at my location - it is all down to the DLM actions.

[#15]

Hi @jab1,

Thank you for confirming that the SNR margin is changing frequently on your side. As this is the case, I think that it would be worth progressing this as a fault and potentially arranging an engineer visit so that this can be investigated further.

Please report the issue here and let us know when you've completed it.