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[JoshShep]

Hi Josh. Mean Time Between Errors (MTBE), is basically illustrating that there is a problem somewhere. Be that with the Exchange equipment, OR's plant or your own equipment, I can't say.

I would request the engineer plug his EXFO/JDSU into the circuit and monitor the error-count. I would ask him to ring the landline number at the same time as monitoring. Also request theyperform a 'Quiet Line test', again, at the same time as monitoring for error-count.

You may get an experienced engineer who has the ability to locate a fault without asking ??

I will show him these notes, hopefully I will get an experienced one this time, does FTT1 Engineer mean anything to you or is that just a standard one trained to work on Fibre?

Thanks Black Sheep!

[Bald_Eagle1]

@ Black Sheep,

I would request the engineer plug his EXFO/JDSU into the circuit and monitor the error-count. I would ask him to ring the landline number at the same time as monitoring. Also request theyperform a 'Quiet Line test', again, at the same time as monitoring for error-count.

Which type of errors will the engineer be looking for?
Error types appear to change, depending on whether Interleaving is ON or OFF.

Strangely, with all the issues my connection has experienced (& is still experiencing) DLM has recently decided to turn Interleaving OFF.
Whether Interleaving is ON or OFF dictates the type of errors.
e.g. with Interleaving OFF, there is no Forward Error Correction (FEC).

Also with Interleaving OFF, Error Seconds increase (no doubt as errors are no longer forwardly corrected).
(See my attached 8 day graphs that demonstrate this - the SNRM dips are all caused by using the telephone, sometimes resulting in a connection re-sync).

You may get an experienced engineer who has the ability to locate a fault without asking ??

Even in Oldham?

I have to wonder if the pre-visit notes from ISPs are actually sufficiently clear, or whether or not those notes actually get passed to the engineer.

I can sort of understand why "some" engineers decline "some" end users' requests e.g. "While you are here, could you please conduct a TDR test as my connection appears to have an intermittent HR issue & by the way, would you like brown sauce on your bacon butty?"

My engineer's visit is provisionally booked for Saturday morning (awaiting confirmation).

I really hope the intermittent issue(s) I am currently experiencing haven't intermittently bu@@ered off again before then.



@ JoshShep,

Good luck for tomorrow's visit.

Is there any pattern emerging that you could mention to the engineer regarding your "intermittent sync and drops in throughput"?
e.g. time of day, heating switched on, use of a hairdryer, an old fridge motor switching on/off, use of the phone, the sky box using the phone line to order a film, sudden or gradual change in prevailing weather conditions/temperatures, next door neighbour is a Radio Ham & when he is transmitting you can see "interference" lines on your TV etc. etc. etc.

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[JoshShep]

@ Black Sheep,

I would request the engineer plug his EXFO/JDSU into the circuit and monitor the error-count. I would ask him to ring the landline number at the same time as monitoring. Also request theyperform a 'Quiet Line test', again, at the same time as monitoring for error-count.

Which type of errors will the engineer be looking for?
Error types appear to change, depending on whether Interleaving is ON or OFF.

Strangely, with all the issues my connection has experienced (& is still experiencing) DLM has recently decided to turn Interleaving OFF.
Whether Interleaving is ON or OFF dictates the type of errors.
e.g. with Interleaving OFF, there is no Forward Error Correction (FEC).

Also with Interleaving OFF, Error Seconds increase (no doubt as errors are no longer forwardly corrected).
(See my attached 8 day graphs that demonstrate this - the SNRM dips are all caused by using the telephone, sometimes resulting in a connection re-sync).

You may get an experienced engineer who has the ability to locate a fault without asking ??

Even in Oldham?

I have to wonder if the pre-visit notes from ISPs are actually sufficiently clear, or whether or not those notes actually get passed to the engineer.

I can sort of understand why "some" engineers decline "some" end users' requests e.g. "While you are here, could you please conduct a TDR test as my connection appears to have an intermittent HR issue & by the way, would you like brown sauce on your bacon butty?"

My engineer's visit is provisionally booked for Saturday morning (awaiting confirmation).

I really hope the intermittent issue(s) I am currently experiencing haven't intermittently bu@@ered off again before then.



@ JoshShep,

Good luck for tomorrow's visit.

Is there any pattern emerging that you could mention to the engineer regarding your "intermittent sync and drops in throughput"?
e.g. time of day, heating switched on, use of a hairdryer, an old fridge motor switching on/off, use of the phone, the sky box using the phone line to order a film, sudden or gradual change in prevailing weather conditions/temperatures, next door neighbour is a Radio Ham & when he is transmitting you can see "interference" lines on your TV etc. etc. etc.

Thanks BE, only thing I can think of is when the weather is dry my connection seems to be more unstable and I have a lower sync, rain seems to do my connection good.

I don't really know about the other things I will have to monitor, what is a TDR test? I think the Engineer will run one if I request he's been quite good actually, that being if it's the same one 

Is the TDR equipment in there standard kit?

Thanks,

Josh

[Bald_Eagle1]

Thanks BE, only thing I can think of is when the weather is dry my connection seems to be more unstable and I have a lower sync, rain seems to do my connection good.

Mine too, but that COULD be pure coincidence.

I don't really know about the other things I will have to monitor, what is a TDR test? I think the Engineer will run one if I request he's been quite good actually, that being if it's the same one 

Is the TDR equipment in there standard kit?

Perhaps Black Sheep could provide a more detailed response, but very basically it is a test that can be conducted using a JDSU (standard engineer's equipment) or "other" specialised equipment that can detect various types of line faults that the usual basic tests such as Pair Quality Test (PQT) often don't detect.

A TDR test that finds a "fault" will also report an approximation of the distance from the testing point etc.

It may different in the area where you are located, but up here in Oldham, visiting engineers appear to have great reluctance (even to the point of a blank refusal) when asked to coduct a TDR test.
Maybe they are not allowed sufficient time per job?

[c6em]

In laymans' language....
TDR Test (Time Domain Reflectometer)
It injects a very very very short electrical impulse into the cable and by measuring very accurately the nature of the reflections received as this pulse bounces back to the instrument from the imperfections (if any) in the cable you can locate the distance of the imperfection from the instrument on the end of the cable.  If you are suitably trained to interpret the waveform trace on the screen of the instrument you can determine the nature of the imperfection on the cable - which might be the obvious direct short/open circuit as well as the dreaded High Resistance fault.
It does require you to know correctly the type of cable being analysed to get accurate results and most tester have some sort of drop down box to choose the cable type (copper/al/conductor size/insulation type etc). cables with multiple cable types in the overall length will also be found as the pulse will reflect back from the change in conductor where it joins.

This sort of specialist instruments don't come cheap - They will be in the £3000+ region as a wild guess but will also need a professional recalibrate once a year as well.

[Bald_Eagle1]

It does require you to know correctly the type of cable being analysed to get accurate results and most tester have some sort of drop down box to choose the cable type (copper/al/conductor size/insulation type etc). cables with multiple cable types in the overall length will also be found as the pulse will reflect back from the change in conductor where it joins.

Could any/every engineer confirm the cable type(s) for individual connections (maybe from BT's Network Records)?

I did ask a visiting engineer if my connection included any aluminium cabling.
His response was "probably", but he wasn't exactly the most helpful of engineers.

[JoshShep]

In laymans' language....
TDR Test (Time Domain Reflectometer)
It injects a very very very short electrical impulse into the cable and by measuring very accurately the nature of the reflections received as this pulse bounces back to the instrument from the imperfections (if any) in the cable you can locate the distance of the imperfection from the instrument on the end of the cable.  If you are suitably trained to interpret the waveform trace on the screen of the instrument you can determine the nature of the imperfection on the cable - which might be the obvious direct short/open circuit as well as the dreaded High Resistance fault.
It does require you to know correctly the type of cable being analysed to get accurate results and most tester have some sort of drop down box to choose the cable type (copper/al/conductor size/insulation type etc). cables with multiple cable types in the overall length will also be found as the pulse will reflect back from the change in conductor where it joins.

This sort of specialist instruments don't come cheap - They will be in the £3000+ region as a wild guess but will also need a professional recalibrate once a year as well.

Very interesting smurfuk, sounds like an advanced test. I will request the Engineer to run this and hopefully it will pinpoint the issue. That being if he hasn't already run this test.

Thanks!

Josh

[Black Sheep]

Hi BE ...... to answer your question, he should be looking at not just retransmitted errors (CRC's/Errored Seconds), but also if Interleaving is applied the FEC's ....... or rather, the rate of incrementation of FEC's. There isn't an integer that we say "Right, it's passed 'X' ammount of FEC's, there's a fault somewhere". You just kinda know it isn't right.

TDR ........ c6em has covered that more than adequately, but if I may add that when actually using the TDR 'we' don't input the cable gauges into the tester. The trace is looked at over the entire distance of the line and conclusions drawn. If it's a Short Circuit, it'll present itself as a 'trough' (Much like the letter 'V'), if it's a 'HR' it shows as a 'peak' ( An inverted 'V'). The trick comes with interpreting the results in relation to cable poundage changes, as miniscule versions of peaks and troughs can appear especially if the poundage change is severe, EG- 0.32-0.64 mm. Cross-referencing can be done against our Network Records for changes in cable sizes, but the experienced engineer should be able to seperate the two.

I always ring the landline whilst the trace is running as this will show a 'HR' that is in its infancy, that a dormant trace wouldn't pick up.

I have a JDSU and they are the bees-knees of the testing fraternity. better IMO than the EXFO that other engineers are always finding fault with. The only down side to the JDSU though is its TDR function, especially at near distances. Thankfully I still have my HAWK for that purpose.

I think it was BE that alluded to timescales on the task ?? Absolutely there are. As a business, there has to be stats and targets to achieve, most know my (and others) take on this, but it is what it is. 2hrs of task time is usually applied to this type of job.

Best of luck.

[Black Sheep]

In laymans' language....
TDR Test (Time Domain Reflectometer)
It injects a very very very short electrical impulse into the cable and by measuring very accurately the nature of the reflections received as this pulse bounces back to the instrument from the imperfections (if any) in the cable you can locate the distance of the imperfection from the instrument on the end of the cable.  If you are suitably trained to interpret the waveform trace on the screen of the instrument you can determine the nature of the imperfection on the cable - which might be the obvious direct short/open circuit as well as the dreaded High Resistance fault.
It does require you to know correctly the type of cable being analysed to get accurate results and most tester have some sort of drop down box to choose the cable type (copper/al/conductor size/insulation type etc). cables with multiple cable types in the overall length will also be found as the pulse will reflect back from the change in conductor where it joins.

This sort of specialist instruments don't come cheap - They will be in the £3000+ region as a wild guess but will also need a professional recalibrate once a year as well.

Very interesting smurfuk, sounds like an advanced test. I will request the Engineer to run this and hopefully it will pinpoint the issue. That being if he hasn't already run this test.

Thanks!

Josh

It's completely the opposite Josh, it's the simplest of tests to perform.

[JoshShep]

Ok thanks for that Black Sheep, much appreciated!

[Black Sheep]

It does require you to know correctly the type of cable being analysed to get accurate results and most tester have some sort of drop down box to choose the cable type (copper/al/conductor size/insulation type etc). cables with multiple cable types in the overall length will also be found as the pulse will reflect back from the change in conductor where it joins.

Could any/every engineer confirm the cable type(s) for individual connections (maybe from BT's Network Records)?

I did ask a visiting engineer if my connection included any aluminium cabling.
His response was "probably", but he wasn't exactly the most helpful of engineers.

Depends on the engineers knowledge pal. If he's a CAL/OMI background, chances are he won't know what Network Records even are. If he's 'Multi-skilled', then yes he should know how to find the relevant info from the Network Records. For your info  ............ it's in the top left hand corner of the application, next to the 'Duct' button. Just in case you get a friendly engineer.

[Black Sheep]

Ok thanks for that Black Sheep, much appreciated!

No worries pal.

[Bald_Eagle1]

Depends on the engineers knowledge pal. If he's a CAL/OMI background, chances are he won't know what Network Records even are. If he's 'Multi-skilled', then yes he should know how to find the relevant info from the Network Records. For your info  ............ it's in the top left hand corner of the application, next to the 'Duct' button. Just in case you get a friendly engineer.

Thanks for that BS.

TBH, as an end user, I shouldn't really need to know any of this stuff.

I should just be able to say something on the lines of "My connection was brilliant, but since it all went off for a few days it has been really poor. Please fix it."

It is only the comments such as "LTOK" when clearly it hasn't been O.K. & "performing within acceptable limits" etc. over quite a few months that has made me look deeper into potential causes.

Also, the explanation of peaks & troughs as shown in a TDR trace was interesting (reflections).
I expected the complete opposite i.e. that a HR fault would show as increased attenuation (a dip or valley), as occasionally displayed in my connection's Hlog graphs:-

[burakkucat]

Also, the explanation of peaks & troughs as shown in a TDR trace was interesting (reflections).
I expected the complete opposite i.e. that a HR fault would show as increased attenuation (a dip or valley), as occasionally displayed in my connection's Hlog graphs:-

You can have it "the other way up". Just invert the Y-axis! 

(It really depends upon what is being plotted against what . . . whether one sees a peak or a trough is not too relevant when one is just looking for an abnormality.)

[JoshShep]

Update: Engineer has been, first he found no faults, and then I asked him to run a TDR Test, he pinpointed a issue 72 metres away, that resulted to the top of the telephone pole. He changed the connection module and found it improved things, run some more tests, rang the phone as doing the tests, all come back fine. I then requested a profile reset which he did, now currently syncing at 40 meg, highest sync I've ever had, still as you know early days, but the next 72 hours will tell. Great bloke that listened to all I had to say, happy at the moment but that can all change, lol.

Fingers crossed!