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SNR/Connection speed wobble.

jab1
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Re: SNR/Connection speed wobble.

The 'interesting' plots since last time.

ConnectionSpeed-2019Aug13-1359.jpgNoiseMargin-2019Aug13-1359.jpgConnectionSpeed-2019Aug14-0000.jpgNoiseMargin-2019Aug14-0000.jpgConnectionSpeed-2019Aug14-0601.jpgNoiseMargin-2019Aug14-0601.jpg

John
jab1
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Re: SNR/Connection speed wobble.

@Townman Re: Your questions to CS in Post 56. I have had a Lift & Shift, pairs have been swapped (twice) and the Frames Unit at the exchange has been replaced. Unfortunately, I can't answer any of the other queries from memory.

The router is on the final f/w and should I really need it replacing, I will obtain a unit which will enable me to to continue monitoring via RSL - I just don't trust unverified ISP reports (no offence, PlusNet)

John
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Re: SNR/Connection speed wobble.

Hi John,

Putting the sync and SNRM plots together is VERY helpful.  They suggest two different profiles - one which causes drops and one which does not.  The latter shows a wider burst of SNRM impact, with a slow decay.  The other is a narrow spike which beings down the connection.

To be honest, the 12dB SNRM is not delivering much benefit here, whilst impacting your sync speed.  Except for the spikes the SNRM is very stable … and the 12dB SNRM is not stopping the drops on all events.  It does though mitigate the wider event, of which there seems to be fewer.  Whilst disconnections are annoying, provided they reconnect promptly, if you are not streaming TV, do they have a material impact on your use of the internet … especially where most are happening whilst you are sleeping?

As to 'Try plotting the FECs as "number in interval" not cumulative.' - how?

To be honest, I do not recall the detail and am not in a position to set up a test environment.  Are you using the TELNET interface for monitoring?  I will drop you a PM later...

jab1
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Re: SNR/Connection speed wobble.

Morning Kevin

Whilst the 12dB SNRM does impact my sync speed - a little - I have been told by three different BT engineers that 8-8.5Mbps is about the best they observe around here for ADSL lines, and to be honest I'd rather have a fairly stable speed as now, rather than the wildly varying unstable 6-12 I seemed to be getting on the 6dB profile, with the changes occurring throughout the day.

No idea what you mean by your last question - sorry, I can be a bit thick sometimes.:smiley:

 

John
jab1
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Re: SNR/Connection speed wobble.

Yesterday and early today:ConnectionSpeed-2019Aug14-1402.jpgNoiseMargin-2019Aug14-1402.jpgConnectionSpeed-2019Aug14-2305.jpgNoiseMargin-2019Aug14-2305.jpgConnectionSpeed-2019Aug15-0105.jpgNoiseMargin-2019Aug15-0105.jpgConnectionSpeed-2019Aug15-0305.jpgNoiseMargin-2019Aug15-0305.jpg

John
jab1
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Re: SNR/Connection speed wobble.

And the next one!ConnectionSpeed-2019Aug15-0505.jpgNoiseMargin-2019Aug15-0505.jpg

John
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Re: SNR/Connection speed wobble.

Plotting FECS - see http://www.vwlowen.co.uk/internet/routerstatshelp/routerstatshelp.htm

Look at "Configuring Telnet" (4th from bottom)

The find "Plotting User-defined Values"

 

This last set of graphs (for me) confirms that there are two differing profiles which might imply different causes.  Questions for you to consider please...

  1. Has the broader event with the slow recovery every happened during darkness?
  2. Have there ever been any of the sharp narrow events during day light?
  3. Do you or your neighbours have PIR lighting or IR CCTV cameras?
  4. Does the router powered on duration suggest that the router remained operational through the narrow events? (Time stamps do not indicate a zero date or show power up sequence)

I hope that plotting FECs will deliver more information here.  The wider event is most certainly REIN - it lasts for a duration and decays gradually.  At a 12dB SNRM the noise level can be accommodated and the link is not dropped.  The narrower event looks very transient, xDSL sync is lost and it has to be considered that this is simply the xDSL session being dropped … for whatever reason.  The link is then re-established immediately, showing no noise problem - this points to a switching spike rather than a REIN issue.

Can you please check the logs for the narrower events and see if there is any cause reported for the loss of xDSL and how long it takes to recover, particularly how many attempts.

 

@Gandalf 

Do DSLAM logs provide any information on the reasons for xDSL drops?

jab1
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Re: SNR/Connection speed wobble.


@Townman wrote:

.  Questions for you to consider please...

  1. Has the broader event with the slow recovery every happened during darkness?
  2. Have there ever been any of the sharp narrow events during day light?
  3. Do you or your neighbours have PIR lighting or IR CCTV cameras?
  4. Does the router powered on duration suggest that the router remained operational through the narrow events? (Time stamps do not indicate a zero date or show power up sequence)

Thanks for your reply, Kevin. To answer your questions in order:

1.Occasionally - see graphs.

2. Not recently, but they did happen prior to the extensive work by BTOR earlier this year - unfortunately, I don't retain plots longer than 2 or 3 months.

3. I, and my neighbour two doors away, have PIR lights, but they were not 'on' when I get these interruptions - I was up and around at the time of the last burst.

4. The last narrow burst certainly dropped the connection - but that is the only one I can check.

 

I'll look at plotting FEC's later - looks like I have a busy day today.

The last two xDSL drops both recovered on the first attempts and from 'xDSL linestate down' to 'configuration saved' was around 1 minute 45 seconds.

John
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Re: SNR/Connection speed wobble.

PIR sensors - is there any possibility that the sensors were picking something up … but not above the threshold which would cause the lights to switch on?

Could you consider turning the PIR activated devices off completely for a couple of nights?

jab1
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Re: SNR/Connection speed wobble.

I can certainly turn mine off, and ask my neighbour to do the same - if I can catch her.:smiley:

John
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jab1
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Re: SNR/Connection speed wobble.

Next 'event' - no xDSL drop! And nothing in router logs.ConnectionSpeed-2019Aug15-1106.jpgNoiseMargin-2019Aug15-1106.jpg

John
jab1
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Re: SNR/Connection speed wobble.

Sorry - ignore that last post, it was RSL 'losing the plot':embarrassed:

John
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Re: SNR/Connection speed wobble.

It does do that!  That is why I recommend setting the alarm and setting an auto restart.  I think that RS leaks memory and gets its router query page sequence out of step - request page Y process the results as page X.

jab1
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Re: SNR/Connection speed wobble.

@Townman Right, after enjoying a very nice Italian (meal!) I can have another look at this annoying problem.

Kevin - I seem to have a problem.:sad: I am running v10.3a of RS Lite, on a TG582n router - I suspect those instructions apply to the full version of RS, as I cannot find the referenced tabs.

Also, unless I am really losing the plot myself, I can't see anywhere to set either the alarms or the auto-restart.

I have turned my PIR off, and asked my neighbour to do the same until Sunday night.

Apologies, again for taking up your time, but I really would like to try and get to the bottom of this - it just doesn't seem to make logical sense to me.

John
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Re: SNR/Connection speed wobble.

Sometimes I wonder what people expect these graphs from a dodgy line to look like! From what I remember, @jab1's line has never been particularly good, so perhaps it has deteriorated a bit recently.