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Standard User caffn8me
(eat-sleep-adslguide) Wed 10-Jan-18 20:28:25
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Womble paging Zarjaz......


[link to this post]
 
Just a quick question; have you ever come across problems where poor xDSL broadband performance is due to a split pair? Or, do you know how common split pairs for POTS are?

I'm starting to suspect that might be an issue on the one line I've had long term problems with.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs

Edited by caffn8me (Wed 10-Jan-18 20:29:06)

Standard User Zarjaz
(eat-sleep-adslguide) Wed 10-Jan-18 20:57:03
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
Yes I have, in one extreme case, ( the pair ‘leg and leg’ for a couple of hundred meters) you could sync up at different speeds (back in fixed speed days ) one sync at half a meg, then drop sync, resync and see 1 meg.

Split pairs are thankfully rare.

You can, with a decent mole/tdr ‘see’ a blip at the start and finish of the split .... but not always. Good old fashioned legwork is the way forward.

What are the symptoms you are seeing ?

Standard User Zarjaz
(eat-sleep-adslguide) Wed 10-Jan-18 21:39:51
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
.... oh yeah, again with an old style mole you can ‘see’ the other pairs digital signal making the read out line ‘tremor’. It won’t show where it is, but will show its presence.

I would expect a line suffering to have a high error count, and a lower than expected sync rate, maybe even random drops ..... so yes, the same symptoms of many other issues ...


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Standard User caffn8me
(eat-sleep-adslguide) Wed 10-Jan-18 21:41:07
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
Thank you very much for the quick reply smile It's greatly appreciated.

This is the problem I referred to back in "crazy Six master sockets on one line"

Downstream is now showing attainable of 36.2Mbps down and 5.3Mbps up. The Openreach DSL tester shows an impacted line should be capable of between 62Mbps and 39.8mbps down and 19.5Mbps and 10.7Mbps up.

POTS tests fine and a quiet line test shows nothing.

The office next door, which is connected to the same DP and DSLAM, has a current sync of 80000/20000.

I'm trying to persuade someone to send an Openreach engineer and a JDSU out to show there really is a problem. This is after having tried with four different VDSL2 modems (al different brands) and replacing all the wiring from DP to master socket (which was copper coated steel).

The DP is on the front of the building between the two offices at first floor level and the multipair feeding it comes over the roof. I'm wondering if someone got a bit distracted while wiring things up a ladder many years ago and there's been a split pair ever since.

We need to start doing offsite backups and the connection speed isn't close to good enough. Next door's works fine for offsite backups.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Wed 10-Jan-18 21:59:36
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
Error seconds are showing at about 15,000 but I'm not 100% sure what period that relates to. CRC errors are several per minute. I've just restarted the router to see what sort of error rate I get from a clean slate.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User Zarjaz
(eat-sleep-adslguide) Wed 10-Jan-18 22:01:02
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
I remember that thread ....

What you’ve got to do I reckon is ;

A. Hope you get an Openreach engineer who has a scooby, and will listen to ..

B. Get the directory number of the 80/20 syncing circuit of the same DP.

.. this is clear evidence that the line question is not right somewhere. They engineer should be able to get the OGEA reference of the other line and run a remote test to prove the 80/20 is possible. Duff DSLAM port ? Naff pair ?

Standard User MC31
(member) Wed 10-Jan-18 22:12:37
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
I did a job were the end user had NDT so i got him DT on a spit pair / leg and leg but he then lost his BB ! so he asked me to put it back on a real pair as for him NDT was better then no BB.

So yes a spit pr is very bad for BB.

these comments are my own and in no way represent any company that i may or may not be linked too.
Standard User Zarjaz
(eat-sleep-adslguide) Wed 10-Jan-18 22:12:49
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
That don’t sound healthy do it.

Standard User caffn8me
(eat-sleep-adslguide) Wed 10-Jan-18 22:18:02
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
The last Openreach engineer had a JDSU and suggested that although things weren't great when he tested, they'd get better as DLM eased up. Of course they didn't.

I thought duff DSLAM port initially and the engineer previously did a port and pair swap. There were two active pairs with POTS coming into the building. One of these has now been ceased. The engineer put the VDSL2 on the better of the two as the pair it was originally on was marginal for DC balance.

I'm a technical contact with the ISP for the line next door too, which helps.

Thank you very much for the pointers.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Wed 10-Jan-18 22:27:32
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
Nope, not healthy. And when Zen ran remote tests previously, the line in this office showed up as 600m longer than the line next door crazy

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Wed 10-Jan-18 22:30:09
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
OK, I haven't just restarted the router frown It seems that all I can do is restart PPPoE which is about as much use as.....

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Wed 10-Jan-18 22:32:52
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
Ha! Found it. Restart is in the ever-so-logical place of being under "Backup" crazy

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 06:14:08
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
So previously the pair AND the port have been swapped out ? So then unless it went from duff port to duff port, that really should have fixed it ?

Were tests made at the DP last time ? Could it be that the other pair in the building is dominant and messing with this one over the underground length ?

I wish I could come and have a play, I do enjoy a challenge that others have failed at, it buffs my smugometer grin

Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 06:15:07
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
Quality.

Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 06:49:14
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
Same make and model of router on both circuits ?

Standard User simon194
(experienced) Thu 11-Jan-18 08:04:36
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
I had exactly that problem on my line causing poor sync speeds.

After my line was fixed following a single leg disconnect the following day the Openreach engineer knocked on my door and asked if my line was OK because it was still showing a fault. It turned out to be a split pair so he put me on a new pair and the sync has gone from 11/3 to 40/10 with some room to spare.

This was a new build I moved into over a year ago and the low sync speed had been put down to the line length.
Standard User caffn8me
(eat-sleep-adslguide) Thu 11-Jan-18 12:15:55
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
This was with a Draytek 2850 on both (not Openreach MCT approved). This is rock steady next door and is currently syncing at 80000/20000

On the bad connection I've so far tried with the following devices' VDSL2 modems;

Openreach modem - Huawei HG612 3b
Draytek 2850
Netgear D7000 (yuk!)
Fritz!Box 3490

It looks like I'll be there on Friday afternoon for the ISP to run some tests and I'll be taking a Cisco 887VA with me.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Thu 11-Jan-18 12:35:24
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
In reply to a post by Zarjaz:
So previously the pair AND the port have been swapped out ? So then unless it went from duff port to duff port, that really should have fixed it ?
Yes, but bear in mind there's never only one split pair smile

In reply to a post by Zarjaz:
Were tests made at the DP last time ? Could it be that the other pair in the building is dominant and messing with this one over the underground length ?
The DP's external at first floor level between the two offices and the multipair feeding it runs over the roof. No tests were done at the DP.

In reply to a post by Zarjaz:
I wish I could come and have a play, I do enjoy a challenge that others have failed at, it buffs my smugometer grin
I wish you could come and play too. I like a good challenge as well smile

Back in about 1997 I had a dual ISDN2e into my office in central London for internet access. It was a new installation and nothing I or the ISP did could get it working with internet. BT kept coming out and kept telling us it tested fine.

Several months down the line, and having swapped out the Cisco routers at both ends several times, I persuaded BT to send someone to do an end-to-end test as that seemed to me to be the logical thing to do. We got their top ISDN engineer from the Mayfair exchange. He really didn't believe there could be a BT fault and said "All thiis is going to do is prove it's your kit that's faulty" - which I thought a bit unlikely.

His next words were; "My gawd, this line's so bad I can't even get voice down it" laugh

It turned out there was a major fault somewhere at the bottom of Telecom Tower and it was affecting lots of customers and BT hadn't been aware of it.

We got so much compensation that it paid for a 2Mbps leased line - which wasn't cheap back in 1997.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Thu 11-Jan-18 12:45:10
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Re: Womble paging Zarjaz......


[re: simon194] [link to this post]
 
I'm glad you got it sorted. You were lucky that the engineer was on the ball.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 12:47:20
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
‘97, the year I started ... I still detest working on ISDN to this very day.

You are right about it could have been swapped onto the splits neighbour, and maybe this is why it doesn’t have so huge an effect, no digital service down the other pair.

Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 12:50:38
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
Can you get full stats from both lines, you have to think that the attenuation is higher on the bum line, hence Zen saying 600m longer.

Sod the router, take a flask wink

Standard User caffn8me
(eat-sleep-adslguide) Thu 11-Jan-18 13:11:13
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
I take my Aeropress with some freshly ground coffee and keep a pint mug onsite laugh

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Thu 11-Jan-18 13:18:59
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
The Draytek I used for intial testing records 'Electrical length' for attenuation.

The last time I checked it with an identical router on both it was 10.2dB for the good connection and 14.2db for the bad one - a significantly 'longer' line. I don't know which frequency that relates to, nor the attenuation rate at that frequency as a function of length.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs

Edited by caffn8me (Thu 11-Jan-18 13:20:51)

Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 13:37:06
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
I wish tea lasted well in a flask ... I just slum it with coffee tongue

Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 13:43:09
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
So nearly half as long again.... how queer.

What might help push your case is having the engineer gain sync with their tester on the good line, note the stats, and compare with the wrong ‘un. Break it down at the DP, and after at the cab. There can’t be too much to fault, three or four hundred meters of D side.

Standard User partial
(experienced) Thu 11-Jan-18 14:10:10
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Re: Womble paging Zarjaz......


[re: Zarjaz] [link to this post]
 
I also found this back in the early days of dsl. Circuit was connecting to neighbours different speed circuit through split legs of only about 20 metres of well twisted dry .63 concentric.
Standard User simon194
(experienced) Thu 11-Jan-18 14:48:10
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
I'm not sure if it's customary to test a line the following day after fixing a fault but I'm glad he did.

Openreach have been doing a lot of work over the the past few weeks at the PCP in preparation for the installation of a second fibre cab in a couple of weeks time, so I'm wondering whether the original disconnect fault was caused by this work.
Standard User caffn8me
(eat-sleep-adslguide) Thu 11-Jan-18 20:12:34
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Re: Womble paging Zarjaz......


[re: simon194] [link to this post]
 
The Mayfair ISDN engineer I referred to previously told me that there had been a strike by BT engineers at one point and they had been asked to return keys to exchanges while they were striking. During the strike the number of faults reported halved. Zarjaz is in the clear on this one smile

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User Zarjaz
(eat-sleep-adslguide) Thu 11-Jan-18 21:37:33
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Re: Womble paging Zarjaz......


[re: caffn8me] [link to this post]
 
If they want to pay me to stay home as fault reduction technique.... go for it. grin

Standard User Zarjaz
(eat-sleep-adslguide) Fri 12-Jan-18 12:09:10
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Re: Zarjaz paging Womble......


[re: caffn8me] [link to this post]
 
Was today the day you got an Openreach visit on this ? If so, how’d it go ?

Standard User caffn8me
(eat-sleep-adslguide) Fri 12-Jan-18 15:40:11
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Re: Zarjaz paging Womble......


[re: Zarjaz] [link to this post]
 
No, today's the day the ISP does tests prior to agreeing an Openreach visit.

I'll he heading over in about an hour with a Cisco VDSL2 router and will let you know how I get on.

Thank you for asking.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Fri 12-Jan-18 18:14:51
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Re: Zarjaz paging Womble......


[re: caffn8me] [link to this post]
 
OK, I've postponed my trip until Sunday as there are still folks working in the office and tech support stops at 8pm.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User caffn8me
(eat-sleep-adslguide) Wed 17-Jan-18 16:22:00
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Re: Zarjaz paging Womble......


[re: Zarjaz] [link to this post]
 
In reply to a post by Zarjaz:
Was today the day you got an Openreach visit on this ? If so, how’d it go ?
We have a winner smile

The engineer has just left. His Exfo tester was only getting 27Mbps at the master socket - which is 10Mbps worse than I was getting on the Cisco. That was good as it was way below the handback threeshhold for an impacted line smile

After a lot of testing onsite he disappeared to the cabinet for a considerable time.

A port reset didn't achieve anything so he shifted to a new port, and bingo!

We're now getting 66Mbps down and 18.7Mbps up with the Fritz!Box. That's about what we should have been getting all along.

Now, the previous engineer allegedly did a port shift back in October 2016.

When I can do some more out of hours testing I'll see what sort of performance we get with the various different router/modem combinations.

Thank you for your help.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User Zarjaz
(eat-sleep-adslguide) Wed 17-Jan-18 17:43:12
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Re: Zarjaz paging Womble......


[re: caffn8me] [link to this post]
 
Glad that’s sorted smile glad too that it wasn’t the split pair as the cause, they can be sods to find.

Standard User caffn8me
(eat-sleep-adslguide) Wed 17-Jan-18 18:42:13
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Re: Zarjaz paging Womble......


[re: Zarjaz] [link to this post]
 
Yes it's good it works now but it should have been sorted back in October 2016 as it was just a faulty port. The previous engineer blamed the poor performance back then on DLM crazy

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User Zarjaz
(eat-sleep-adslguide) Wed 17-Jan-18 19:45:48
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Re: Zarjaz paging Womble......


[re: caffn8me] [link to this post]
 
That’s shocking really.

Standard User caffn8me
(eat-sleep-adslguide) Mon 29-Jan-18 09:51:50
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Re: Zarjaz paging Womble......


[re: Zarjaz] [link to this post]
 
Just a quickie question, do Exfo testers generally sync at a lower rate than they probably should? the reason I ask is that when the engineer put the Exfo on the line, he got a sync rate about 8Mbps less than I'd just got with a Cisco - on an ECI cabinet.

Sarah

--
If I can't drink my bowl of coffee three times daily, then in my torment, I will shrivel up like a piece of roast goat

Spiders on coffee - Badass spiders on drugs
Standard User Zarjaz
(eat-sleep-adslguide) Mon 29-Jan-18 11:30:06
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Re: Zarjaz paging Womble......


[re: caffn8me] [link to this post]
 
In all honesty Sarah, I have never used an Exfo ...

My old MK1 JDSU clearly did not achieve the same VDSL sync rates that customers newer routers does ... I now have an MK2, 2nd hand, and that seems somewhat better. The important thing in their use I think, is to appreciate that different appliances achieve different sync rates, but have yourself a known ‘trustee’ as a benchmark.

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