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Author Topic: BT DSL tester shows no errors, huge error rates from my router  (Read 4073 times)

aesmith

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BT DSL tester shows no errors, huge error rates from my router
« on: December 23, 2016, 02:00:41 PM »

Hi,

At the end of a recent visit the OR engineer ran a 5 minute DSL test on our line, he took the end of my RJ11 cable out of the router for his tester so cable, filter and everything we same as my installation.   His test ran effectively clean, one downstream CRC in five minutes, compared to their previous visit where it ran up a couple of hundred, and he synched at I think 4.3meg  All looking good.

However with my own router I get zillions of errors and a lower rate.   As soon as I saw that I swapped to  my spare router, a 582N and that showed the same and a worse synch rate ..

Yesterday 19:19:13
BT Test xDSL Status Check:Pass OK.pass OK. Circuit In Sync
BRAS=2500kb/s FTR=3200kb/s MSR=4000kb/s ServOpt=1 I/L=A
UNABLE TO REACH THE CHOSEN SERVICE OPTION BUT WILL CONTINUE TO FUNCTION UNDER DLM CONTROL (ILQ=R)
Up Sync=448kb/s LoopLoss=31dB SNR=19dB HIGH ErrSec=0 HECErr=0 Cells=103738
Down Sync=3232kb/s LoopLoss=56.5dB SNR=6dB ErrSec=737 HECErr=0 Cells=2577316


After a couple of hours swapped back to the Billion.   It occurred to me that the BT tester was used on the floor clear of any of the powered up equipment (phone, printer television stuff) whereas my router is nearby.  So I powered off all mains powered gear including lights in the room and the adjacent hallway, only the router powered up.  No improvement ..

Today 09:52:31
T Test xDSL Status Check:Pass OK.pass OK. Circuit In Sync
BRAS=2500kb/s FTR=3200kb/s MSR=4000kb/s ServOpt=1 I/L=A
UNABLE TO REACH THE CHOSEN SERVICE OPTION BUT WILL CONTINUE TO FUNCTION UNDER DLM CONTROL (ILQ=R)
Up Sync=448kb/s LoopLoss=30.5dB SNR=20dB HIGH ErrSec=0 HECErr=0 Cells=235326
Down Sync=3904kb/s LoopLoss=55.5dB SNR=7dB ErrSec=696 HECErr=0 Cells=4991342


Either BT or A&A, not sure who have raised the target to 9dB, still no improvement at that lower speed ..

Today 12:24:45
BT Test xDSL Status Check:Pass OK.pass OK. Circuit In Sync
BRAS=2500kb/s FTR=3200kb/s MSR=4000kb/s ServOpt=1 I/L=A
UNABLE TO REACH THE CHOSEN SERVICE OPTION BUT WILL CONTINUE TO FUNCTION UNDER DLM CONTROL (ILQ=R)
Up Sync=448kb/s LoopLoss=31dB SNR=19dB HIGH ErrSec=0 HECErr=0 Cells=308230
Down Sync=3520kb/s LoopLoss=55.5dB SNR=9dB ErrSec=732 HECErr=0 Cells=3827221


Any ideas about the sort of fault that would cause these issues when using my gear, but show clean on BT's DSL test?   I guess it's looking very much like my equipment is at fault, but two different routers showing the same symptoms is a little off.
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burakkucat

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #1 on: December 23, 2016, 04:35:50 PM »

I wonder if it is a question of what is the chipset & analogue front-end in your modem/router(s) and in the "BT tester" used by the Openreach technician. I presume it was either a JDSU HST-3000c (with the current Broadcom based HST3000-WB2 SIM) or an Exfo AXS-200/635?  :-\
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GigabitEthernet

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #2 on: December 23, 2016, 04:37:55 PM »

I am not convinced the errors on the Openreach equipment are accurate. I remember when I had a fault and the tester displayed one FEC in 15 minutes. I put three different routers on and straight away I had hundreds within minutes.
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burakkucat

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #3 on: December 23, 2016, 04:48:45 PM »

I am not convinced the errors on the Openreach equipment are accurate.

It really depends upon the SIM of the JDSU (if a HST-3000c was used) being up to date and Broadcom based. I know, for example, that Black Sheep was provided with the latest (Broadcom based) WB2 SIM to replace the Infineon one he was then using.
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Black Sheep

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #4 on: December 23, 2016, 05:26:48 PM »

I tend to find this same scenario with CISCO routers used in business premises. They have to be set to at least 9dB on the DS SNR, but prefer to be at 12dB DS SNR to be completely error-free.

I have no idea as to the technical reason behind this, it just is. Proven hundreds of times over many years of faulting.

Now for the really strange thing, and maybe what's happening with the OP ........... I've had this a couple of dozen times over the years.
I run a '5 minute DSL Close-out test' as required in the job standards, and the circuit is completely error-free, bearing in mind we only see CRC/FEC on our screens .... not HEC. This test logs on to the ISP's server.
Now, when I run a bog-standard xDSL test, which only 'talks' to the DSLAM in the Cab/Exchange ..... I see incrementing errors ???

Alas, I can't remember what the fixes were on all occasions, but there were definitely miniscule HR's on a few of them. I don't want to get the OP's hopes up, as this is just me recounting a few anomalies.  :) It could very easily be down to the EU's equipment ??.
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aesmith

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #5 on: December 24, 2016, 08:00:11 AM »

BT tester showed zero FECs, which did strike me as a bit odd.  Regarding the kit, both the Billion and Thomson routers have worked for me in the past with normal 6dB target so I don't think the type of kit is the issue, although of course it's possible they're both faulty.

I'm running a brief test at 12dB and so far it look like error rate is unchanged.   Will give that 30 mins at least.

Sent from my Nexus 7 using Tapatalk

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aesmith

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #6 on: December 24, 2016, 08:59:00 AM »

As initially thought, even 12dB doesn't clean it up.  At that point we're down to 2.8meg from normal 4meg, and below FTR.  Long shot maybe, but I'm going to see if I could test my router on a neighbour's line.  Can't really think what else I can do to rule out our equipment because I agree, on the face of it with BT test passing and my kit failing it looks like my kit.
« Last Edit: December 24, 2016, 09:01:31 AM by aesmith »
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ejs

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #7 on: December 24, 2016, 09:23:28 AM »

I suppose that unlike the BT handheld tester, both the Billion and the Technicolor were powered by their mains switched-mode power adapters?
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aesmith

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #8 on: December 24, 2016, 03:42:30 PM »

Yes they are (were) although only one was plugged in at a time, ie Billion PSU not plugged in when using Thomson router.  Anyway things have moved on.  It certainly appears that A&A push things along quicker than I'm used to .. OR engineer turned up this morning with a different model tester, his DSL test showed loads of errors, CRCs and FECs.   Mirroring ejs's thoughts he tested with and without the Billion PSU plugged in, and saw no difference.  Everything else in the room and adjacent room was powered off anyway.

They're now thinking REIN but nothing's going to happen for a while.  Today's engineer said he's keeping the call and will try to get hold of a REIN tester to do some checks himself.   Is there a different term for continuous interference?   I don't see the sharp drops and rises in SNR that others have shown when suffering from REIN.
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ejs

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #9 on: December 24, 2016, 04:47:06 PM »

I don't think you need a different term, REIN can be 100 impulses per second, which would appear as continuous in terms of clocking up CRC/FEC errors, even if you polled the stats every second. I get the occasional odd period with a greatly elevated FEC rate but little change in the SNRM.
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aesmith

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #10 on: December 29, 2016, 03:28:50 PM »

Seems to be a stalemate after that original REIN speculation.   REIN helpdesk have said it's not REIN. All they've managed to find out is that testing at our pole they get errors, and this persists even after swapping pairs between pole and exchange, and swapping port at the exchange.  To me that sounds like an issue between pole and exchange, but engineer's notes are saying either customer equipment or CP server as the underlying issue.  Surely if they're testing at the pole (1/2 mile from the house) it can't be customer equipment causing the errors, and surely A&A's servers can't be causing CRC errors both up and down on the DSL.  Or am I missing something?
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aesmith

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #11 on: January 03, 2017, 03:54:43 PM »

A&A now pushing for a "lift and shift",  as opposed to a "TPM" which apparently causes 24 hours or more of downtime.   Not sure why, given "lift and shift" is exactly what the engineer notes said was done on 29th.   I guess it may be just one of the hoops they have to jump through, in the email A&A said they wanted to get us moved onto a different card but he was concerned about downtime.   
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Black Sheep

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #12 on: January 03, 2017, 07:22:27 PM »

A&A now pushing for a "lift and shift",  as opposed to a "TPM" which apparently causes 24 hours or more of downtime.   Not sure why, given "lift and shift" is exactly what the engineer notes said was done on 29th.   I guess it may be just one of the hoops they have to jump through, in the email A&A said they wanted to get us moved onto a different card but he was concerned about downtime.

I don't know why ?? If the 'Lift & Shift' is to a different card in the same FTTC Cab, then the downtime is exactly the same as it would be for a 'Lift & Shift' auto-allocated to the next available port, on the same card.  ::)

The time element only applies to our DCoE advisors, who have to manually go through the available ports and temporarily mark them as 'faulty', up to the point the auto-allocator would only see the next available port as being on a different card.

Even if there were quite a few to be marked as 'faulty' ...... this is a 10 minute job for the guys, and as I say has no bearing on your downtime. The downtime begins when the new port is actually allocated (on whatever card is chosen), as the robotic tools at play start 'Lifting and shifting' your details from the old port to the new one ...... a task that is averaged out at about 20mins.
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aesmith

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #13 on: January 04, 2017, 08:53:11 AM »

Cheers Black Sheep (and Happy New Year).   The trouble from my point of view is that I'm interpreting 3rd of 4th hand information, what A&A tell me that BTW told them that Openreach said or did, so plenty of scope for me to misunderstand (for example A&A's emails refer to changing card vs changing to different port on the same card, while the case notes refer to TPM vs Lift and Shift).  I do wonder whether our 20CN exchange made be more manual that you're thinking of as well.
Quote from: A&A to me
BT want to put your circuit onto another line card and port but I am just checking with them to make sure they do not disconnect the existing port first, as otherwise you could be completely off line for 24 hours or more.

Quote from: BT (shown in case notes)
Please confirm can I go ahead and place TPM order. But once I will place TPM order, circuit will go down. Please confirm so that i can take action accordingly.  We are not re-arranging the Port to move the customer to different VP. It's with the same VP but customer will move to different port and customer circuit will go down.  Please confirm can I go ahead for TPM or I will raise LL13 for Lift and shift.

Quote from: A&A to me
They are going to just move it to a new new port by way of a lift & shift, minimal down time.

Case notes suggest two working days time scale for this, and it needs engineer at the exchange.
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Black Sheep

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Re: BT DSL tester shows no errors, huge error rates from my router
« Reply #14 on: January 04, 2017, 10:01:42 AM »

Oops, my bad ............ I've been assuming you're talking about FTTC, not ADSL. That'll teach me (again) for not being ar5ed to read the thread fully.

Either way though, whatever the product ............ the timescales are the same for any port change ............ same card or different.

HNY.  :)
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