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Author Topic: Need Help Diagnosing Fault  (Read 24596 times)

soreilly

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Need Help Diagnosing Fault
« on: April 15, 2012, 05:08:58 PM »

Good Afternoon Guys,

I need some help diagnosing a fault which has appeared over the last couple of weeks and now appears to be getting worse.

Firstly here are the important details

ISP: Xilo (on Be LLU)
Attenuation: 34.0dB Down / 16.0dB Up (under normal conditions)
Sync Speed: 10Mbps Down / 1Mbps Up (under normal conditions)
Router: Cisco 887W (also have a spare Netgear DG834v4)

Up until about 3 weeks ago I had a fairly stable internet connection then one afternoon there was a short period (~30 - 45 minutes) where several disconnections were seen and the speed and attenuation fluctuated.  At the end of it, the router reconnected at its normal speed and attenuation and everything was stable.  I didn't think too much of it at the time.

Fast forward to Easter where this happened again but this time it went on for about 3 hours.  My sync speed went from 10Mbps down to 2Mbps and everything in between with the attenuation rising to over 40dB.  Eventually it calmed down and returned to normal.  I raised a fault with my ISP (which is still open) and they advised that if the router is loosing sync then it's something "local". 

A few days ago it started getting worse and on Friday I had the day off so decided to troubleshoot.  So to start with, I disconnected everything and plugged a phone (no microfilter) into the test socket and did a quiet line test (here after referred to as QLT).  This was absolutely silent.  I then plugged a microfilter into the test socket, connected a phone and did the QLT again.  Again this was silent.  I had seen the disconnections on both the Cisco 877 and the Netgear.  I tried both routers during the troubleshooting and was able to hear "broadband noise" from both of them. 

I kept the QLT open and plugged the ADSL connection in.  When the DSL was connected (and when it was connected) I could hear a constant noise (like static) on the line.  If I hung up and redid the QLT, it would drop the broadband connection (at which point the QLT became silent).

At this point, I'm thinking the filter is dodgy so I grab some spares I've got and change them over.  After some further testing (with the broadband in the main socket instead of the test socket), I finally get a quiet line and making a phone call no longer kicks the broadband off.  Excellent I thought.  Connection remained stable for about 14hrs before the symptoms reappeared - frequent disconnection / fluctuating speeds / noise on the line with the broadband.

On Saturday, I decided to go one further and replace the cabling and re-terminate all the connections.  So, with Krone tool in hand I started with the connection from BT that terminates on the NTE5 (yes I know I shouldn't touch this).  Did that and then did a QLT - absolute silence with and without microfilter).  Then redid the extensions.  Performed a QLT from each socket (without the broadband) and each one was quiet. 

All the sockets worked, no noise on the QLT, reconnected the broadband and left it alone. 

Today I'm in work (until 7pm) and decided to check the router and noticed that it had been bouncing wildly this afternoon.  I can't check to see if there is any noise on the line, but I suspect it may be present.

So to sum up, line is silent when just using a phone for a QLT, but when the DSL is active, noise can be heard.  I'm guessing it's internal to me, so what could it be and how do I stop it? 

Edit: I'm assuming the fault is local to me, could it in fact be something like a HR fault on the line?

I've tried about 6 different microfilters at home, 3 different ADSL cables and 2 different DSL routers. 

Many thanks for reading and sorry for the long post.

Regards,

Stuart
« Last Edit: April 15, 2012, 06:37:44 PM by soreilly »
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Current ISP: Xilo LLU (via Be LLU)
Previous ISP: Zen (for 9 years).

burakkucat

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Re: Need Help Diagnosing Fault
« Reply #1 on: April 15, 2012, 07:52:05 PM »

The fact that the loop attenuation has shown variations, coupled with the "static-like" noise you can hear when the circuit is attempting to operate as it is designed (modem/router in sync with the DSLAM, telephone "off hook" and in use), is clearly indicative of a developing HR joint somewhere external to you in the Openreach cabling.  :(

Ideally you would require the services of a SFI Openreach engineer to run some stress tests on your line whilst monitoring it with her/his JDSU, Exfo or Hawk in TDR mode.

Perhaps Black Sheep will offer his opinion, please?
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waltergmw

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Re: Need Help Diagnosing Fault
« Reply #3 on: April 15, 2012, 11:37:07 PM »

Gentlefolk,

For completeness, it might also just be worth checking for star wiring inside or outside the house itself, even though this quite unlikely.

Kind regards,
Walter
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soreilly

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Re: Need Help Diagnosing Fault
« Reply #4 on: April 16, 2012, 08:17:26 AM »

Hi Guys,

Thanks for the replies. 

@Jeffbb - I have heard of (and used) RouterStats in the past.  I'll try and get the Netgear reconnected this evening and see if I can run RouterStats tomorrow to record any variation.  At the moment the fault appears to be intermittent.

@Walter - From what I can see, it's a fairly simple setup.  There is a BT pole outside the house which feeds about a dozen properties in the close.  The overhead cable comes from the pole to a juction box(?) under the eves on the property and from there, the BT cable comes down the outside of the house to the front room where it enters the property.  It goes into another small box which has jelly crimps inside it and from there to the NTE5.  Internally from the NTE5, there is a single extension to a phone socket upstairs.

Regards,

Stuart
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snadge

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Re: Need Help Diagnosing Fault
« Reply #5 on: April 16, 2012, 09:39:44 AM »

Ive had similar problems as you recently and I could fix it by messing about with it also..then later it would start again...for me it turned out too be a "crossed wire" after switching me from BT Wholesale to SKY SVBN, they went too fix this and now I have no phone line and slow broadband as they require access to my home to complete the job. For me I had your symptoms but also the phone rang randomly twice and when we 1471 it we could hear noise and conversations on the line, incoming calls dropped the broadband, also, sometimes when I picked up the phone there was noise & engaged tone....not much help here but just pointing it out.

sorry I can not be of much help, it sounds like burakkucat may have defined what it is  - you just need to convince your ISP of this so they can get a engineer out
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soreilly

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Re: Need Help Diagnosing Fault
« Reply #6 on: April 16, 2012, 11:00:21 AM »

It appeared to "go stable" late yesterday afternoon and remained stable overnight.  At 10:45 this morning the connection dropped, the attenuation went up a couple of dB's and the sync speed dropped from 9Mbps to 5.9Mbps.  As I type this, it's gone again, now up +3dB on attenuation to 37dB and sync speed down to 4.5Mbps.

Unfortunately I'm at work (on 12hr shifts) until Wednesday so can't do anything before then.  I'm hoping to see if a pattern emerges - like between 10:00hrs - 17:00hrs and then I can grab some further diagnostics on Thursday / Friday.

Stuart,

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burakkucat

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Re: Need Help Diagnosing Fault
« Reply #7 on: April 16, 2012, 06:43:10 PM »

It still reads as a HR, semiconducting or otherwise marginal joint in your D-side cable.  :(
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soreilly

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Re: Need Help Diagnosing Fault
« Reply #8 on: April 17, 2012, 06:32:41 PM »

Hi Guys,

There is definately a problem.  I ran RouterStats on the Netgear today.  It was raining this morning and the SNR stayed stable.  But after lunch when it dried up, the SNR and attenuation started jumping all over the place before settling down a few hours later.

So, what's the best way to report this my ISP (Xilo) to ensure I get an engineer who is clueful about these type of faults and not somebody who just sticks his test equipment, confirms the service is working and buggers off leaving me with a massive bill?

Stuart,
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burakkucat

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Re: Need Help Diagnosing Fault
« Reply #9 on: April 17, 2012, 07:07:34 PM »

Continue to monitor your line with routerstats, print out copies of the graphs that show the effect of the intermittent error and send copies of the same to your ISP. (It wouldn't go amiss to suggest that they also monitor this forum thread.)

A weather diary, collating line abnormalities with temperature, humidity, high winds or whatever, would also be worth keeping.

You will need the services of an SFI Openreach engineer.

Perhaps Black Sheep will be able to add a few helpful comments?
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soreilly

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Re: Need Help Diagnosing Fault
« Reply #10 on: April 22, 2012, 04:33:18 PM »

Hi Guys,

I've been collecting some data over the last few days with RouterStats and have put it up here:
http://www.stuart.aurora-solutions.co.uk/dsl/index.html

It has a link to each day, gives a brief summary of the weather and the stability of the broadband.  As you can see, the broadband is stable when the circuit is wet.  Each page has screenshots of the RouterStats output showing the stability.

Today was really quite bad so I decided to use my camera phone to try and capture what I was hearing.  Anyway, that was done at about 1pm today.  The filter you see at the start of the video was brand new and still in its wrapping when I borrowed it from work on Friday.  The video shows me swapping out for an ADSL Nation filter which doesn't make much difference.

When I was recording this, during a QLT I heard a really weird noise and want to know if someone can identify it.  On the video it starts around the 2:10 mark.  At this point only the phone is plugged into the filter into the test socket.

It started raining (very heavily) at 15:25 and the circuit has been stable since then. :(

I also used the DMT Tool to query the Netgear when it was playing up and this is what I got (file: DMT_With_Fault.png).  I then queried the Netgear again after the circuit had been rained on and got this (DMT_After_Rain.png).  I'm no expert, but certain tones that were missing this morning are now present and I get a higer bit loading after it rained?!?!

Video Link: http://dl.dropbox.com/u/69515152/Broadband.wmv

Thanks,
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Black Sheep

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Re: Need Help Diagnosing Fault
« Reply #11 on: April 22, 2012, 04:49:58 PM »

Apologies B*Cat, only just seen this thread.

"So to sum up, line is silent when just using a phone for a QLT, but when the DSL is active, noise can be heard.  I'm guessing it's internal to me, so what could it be and how do I stop it? 

Edit: I'm assuming the fault is local to me, could it in fact be something like a HR fault on the line?"


Yes, I would say that's the case, re: the HR. You shouldn't be able to hear the white noise from the router when using the phone, absolutely not.

The problem is how to progress this !!

As it sounds like a HR in its early stages, the chances are the line will test ok on a normal remote test. You could enquire if you SP has access to the CIDT testing systems that perform the normal test, then ping the router with various frequency tones which will determine if there is indeed a HR on your line.

As B*Cat says, ideally you need an SFI engineering visit. If you get a Network engineering visit, the chances are you will get billed and nothing done. I wont go into the semantics behind this, just take my word for it. ;)

If you imagine a HR as being a worn through wire like this .........  }{ .......... with the gap in the middle being the HR. When it rains the water 'fills' the gap thus giving a more stable line ......... ==== ....... ie: the width of the wire is constant. Apologies for the awful icons, but I cant demo it any other way. :-[

So, to concur with others, request an SFI and stress the point audible noise is present with the router plugged in, and that this is causing extreme ammounts of interleaving. It then depends on the quality of engineer you get, and his relevant knowledge. You could ask that interleaving is switched off and that you run in 'Fast path' mode, so that the errors are way more noticeable to both the ISP and the engineer. He may well ignore RS (FEC's), but shouldn't ignore CRC's (Errored Seconds) which will be racking up nicely once Interleaving is removed.

Your choice mate. ;) ;D

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burakkucat

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Re: Need Help Diagnosing Fault
« Reply #12 on: April 22, 2012, 06:01:01 PM »

I've been collecting some data over the last few days with RouterStats and have put it up here:
http://www.stuart.aurora-solutions.co.uk/dsl/index.html

<snip>

Video Link: http://dl.dropbox.com/u/69515152/Broadband.wmv

Both your graphs and video are excellent evidence of a cable fault external to your home.

I would suggest that you make contact with your ISP by e-mail, allow them to digest the information and stress that the fault is only present on warm, dry days. (Provide them with the links to your graphs, the video and this forum thread.) As Black Sheep has mentioned, they may be able to use CIDT to observe the fault for themselves.

Make a request for them to book a visit from an Openreach SFI engineer to trace and eradicate a HR fault.

As your ISP is Xilo (a.k.a. Uno) they should listen and thus be suitably reactive to your complaint.

[EDIT: The odd sound is - er - odd. Sorry but I do not recognise it.  :no:  ]
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Bald_Eagle1

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Re: Need Help Diagnosing Fault
« Reply #13 on: April 22, 2012, 06:55:35 PM »


If you imagine a HR as being a worn through wire like this .........  }{ .......... with the gap in the middle being the HR. When it rains the water 'fills' the gap thus giving a more stable line ......... ==== ....... ie: the width of the wire is constant. Apologies for the awful icons, but I cant demo it any other way. :-[


FWIW, apart from the noise on a Quiet Line test when the router is connected, this all sounds quite similar to my FTTC connection (i.e. the possible link to wet & cold weather that seems to create a more stable connection).

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burakkucat

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Re: Need Help Diagnosing Fault
« Reply #14 on: April 23, 2012, 01:08:34 AM »

Quote
. . . this all sounds quite similar . . .

@Bald_Eagle1, To eliminate any potential for possible confusion by someone speed-reading this thread, I believe you intend the above to be --

Quote
. . . this all reads quite similar . . .

I think the distinction is necessary, for the OP has posted a link to a video, complete with an audio soundtrack!  :-X
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