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Standard User rlees85
(newbie) Sun 07-Feb-16 11:15:12
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Strange ADSL Dropous - Any ideas? (Pretty Graphs included)


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Hi All

Really hoping some DSL exports or even lurking BT engineers get to see this...

In summary I have frequent losses of sync on my line. My line is an average distance from the exchange (not sure exactly) and line attenuation is always pegged at 39.6 down and 22.1 up. The SPEED of my connection is fine, normally ~10mb, but can reduce to ~6mb if DLM kicks in due to frequent drop-outs.

Things tried so far:
- BT MK3 Faceplate
- 2x different modems, exactly the same behaviour.
- Disconnection of internal telephone wiring past master socket (I don't use it anyway)
- Changed twisted pair to property
- Changed twisted pair from cabinet
- Changed twisted pair from exchange to cabinet
- Visual inspection of exchange port and changed what is possible without a full lift and shift.
- Messing around with an AM radio set to 612Khz MW, nothing abnormal at my property.
- No REIN detected by Openreach on the line.
- Quiet line test is always perfectly quiet, even when internet is disruptive. Using the phone/etc has NO impact on my broadband.

Attached is a detailed graph of a 'typical' day. The data is gathered from a D-Link DSL320-B and I have not used routerstats due to it not properly supporting Linux (Wine is not Linux support).

>> Main Graph <<

A series of purple crosses marks a blackout. A single purple cross is not a blackout, its just that my computer failed to hit its test page once. There is one blackout (a big one where DLM adjusted my SNR margin) that is not "shown" on the graph but it happened.

SNR margin scale on the left
HEC errors scale on the right
HEC errors corrospond to DOWNSTREAM HEC errors, UPSTREAM HEC errors is always pegged at 0.

What this tells me:
- It isn't a HAM radio operator. Infact it isn't any sort of REIN or SHINE. There are no sudden or major drops in SNR margin.....
- ... however SNR margin does seem to drop SLIGHTLY for a while before a drop-out. This should not cause an issue on the 9db profile as it never went below 8db, but still died in a big HEC error-y mess.

Like here:

Dropout 1: Graph Dropout 1 SNR margin gets a tiny bit worse before the big drop. HEC errors begin rising.

Dropout 2: Graph Dropout 2 SNR margin gets dangerously low all evening, again HEC errors start to rise and finally bang. This time DLM decides to move me from 6db to 9db.

Dropous overnight: Graph Overnight Drops Loads of dropouts throughout the night, the SNR margin seems 1DB down from target during the unreliability but it IS still at 8db which is more than enough! After the re-sync at 07:15 AM the SNR margin seems more consistent and connection reliable.

I must re-iterate that even though there seems to be a slight link with SNR margin and drops, the SNR margin is NOT below spec (on the 9db profile at least) and is NOT dropping like a stone, only a tiny bit here and there.

... so, any ideas??? For the record, my ISP is working with me on this (thank god) but they are getting stumped now. They are offering a lift and shift next but I want to be sure my graphs correspond to a broken DSLAM port before going ahead with days of downtime.

Cheers !
Standard User rlees85
(newbie) Sun 07-Feb-16 11:22:13
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: rlees85] [link to this post]
 
Should also mention, that more frequent dropouts during early hours of the morning is a pattern (happens every day).

This is an example of a GOOD day. Some days can have more than 20+ drop outs and 10 of them being when I am trying to use it (17:30pm - 23:00pm)

Edited by rlees85 (Sun 07-Feb-16 11:37:29)

Standard User rlees85
(newbie) Mon 08-Feb-16 21:15:08
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: rlees85] [link to this post]
 
Judging by the views/comments ratio people have as much clue about this as I do...

My ISP called today and offered a lift and shift. Luckily for me they seem to be really driving my issues with Openreach now smile

Anyway just for giggles heres the next 24 hours (and the last I'll add):

>> Next 24 hours overview <<

>> Dropout 1 SNR margin seems to have little signifficance with this and many other drops

>> Dropout 2 A drop followed by a weird re-sync. Upstream has synced at a higher speed (and lower SNR margin). Downstream back down to SNR margin 6db but only 6mbps.

>> Overnight Drops The usual many drops in the early hours. One drop caused a stupid amount of HEC errors ruining the graph. Looking closely, same as all the other drops, they are always accompanied by between 100s-10,000s of HEC errors.

Anyway, I'll post back if a resolution is ever found... just for the people who end up here from Google.


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Standard User BatBoy
(sensei) Mon 08-Feb-16 21:28:32
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: rlees85] [link to this post]
 
As far as I can see, you haven't changed the modem, the modem cable or the master socket. Everything else perhaps, so maybe one of those and a lift&shift is all that's left, before migrating to a different ISP.
Standard User rlees85
(newbie) Tue 09-Feb-16 22:10:43
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: BatBoy] [link to this post]
 
I've tried a selection of 3:

A D-Link DSL-320B using 1.06 firmware (standard D-Link)
A Buffalo WBMR-G54 running OpenWRT
And some old [censored] Linksys thing I had lying around

All the same frown

Also the BT MK3 socket is new, and BT gave me a new RJ11 cable too.

Thanks for the reply anyway - if the lift and shift fails how would migrating to a new ISP help if its over the same line? Just out of interest as I still don't really get how ADSL works.
Administrator MrSaffron
(staff) Tue 09-Feb-16 23:13:47
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: rlees85] [link to this post]
 
If the other ISP has their own DSLAM then the ADSL and how it handles noise may be configured differently.

Also none of those modems have a memorable reputation for ADSL performance, the old 2Wire kit was usually the go to kit for problematic lines.

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User rlees85
(newbie) Sat 05-Mar-16 17:37:30
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: rlees85] [link to this post]
 
So just a bit of an update on this.

We had the lift and shift done - no improvement.

This left me a bit baffled. New twisted pair from house to exchange and new port but still random drop outs (noticeably worse with rain (not rein, RAIN lol)).

So at this point I removed the plastic cover from the DP on my house to discover that my line was still on its original twisted pair. Openbreach just pretended they did it. They seem good at lying on notes.

Since then my ISP has been fighting to get the line checked and crimps/pairs changed but with no success. My ISP has even been on the phone to Openreach engineers that have been to my house asking them to do at least something but they point-blank refuse. "Our tests show the line is fine, so we are going now..." oh great must be imagining the 20 drop-outs per day then. Idiot.

In summary:
The problem is my line, 99% sure.
My ISP really have handled this 10/10 and have done all they can. I dont even need to chase them, they call me saying they notice the line is still poor.
If you have an Openreach line that is faulty but not to the point it has totally failed, then god help you.

Changing to a modem that handles noise better isn't going to help as the problem isn't noise. Also changing ISP isn't going to help as we only have BT wholesale here no other LLUs frown
Standard User Apprentice
(knowledge is power) Sun 06-Mar-16 08:52:31
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: rlees85] [link to this post]
 
Also changing ISP isn't going to help as we only have BT wholesale here no other LLUs frown

Which ISP are you with?

plusnet user
Standard User rlees85
(newbie) Sun 06-Mar-16 11:20:27
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: Apprentice] [link to this post]
 
Zen at the moment !
Standard User Zarjaz
(eat-sleep-adslguide) Sun 06-Mar-16 15:19:02
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Re: Strange ADSL Dropous - Any ideas? (Pretty Graphs include


[re: rlees85] [link to this post]
 
How does 'removing the DP lid' prove you are on the same pair ?

If your ISP is doing so much, and I believe yours has a good reputation, why have they not arranged for further visits ? There is no point 'ringing the previous engineers', they are unable to just return to a previous task like that.

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