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[waltergmw]

Gentlefolk,

Here with the sad tale I mentioned in my previous post re the BT Wholesale estimator.

Walter's wheelbarrow trundled to a Surrey Hills house suffering from very poor VDSL line speeds which had just been installed by a loan engineer from East Anglia.
The exhausted chap arrived late for a morning appointment as this was the SIXTH that he had been scheduled to attend.
However, unsurprisingly, "he was very quick to complete the job".
(I.e. I exonerate the individual concerned due to the near-impossible workload he is expected to complete.)

The wheelbarrow examined the service with the excellent help from the Eagles and pussy cats frequenting this site.
It was immediately obvious that a bridge tap condition existed which was confirmed when star wiring before the NTE5 was discovered.
Once the offending extension was isolated there was an immediate increase in sync speed, although it was now apparent that the service was being limited to 20 Mbps still.

Very sadly we are unable to obtain any Openreach assistance to remove the limit as the sync speed is just above the maximum (B Range) quoted by the ISP involved.
More alarming is that the highly reputable ISP seems unable to access the figures we observe from the unlocked Huawei 612 modem.
Our only option now is to continue monitoring the service well past the training period before initiating yet another discussion.

Max:    Upstream rate = 6596 Kbps, Downstream rate = 26344 Kbps
Bearer:    0, Upstream rate = 6604 Kbps, Downstream rate = 19998 Kbps

Discovery Phase (Initial) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3970)
Medley Phase (Final) Band Plan
US: (7,32) (871,1205)
DS: (33,859) (1216,1961)
                  VDSL Port Details          Upstream          Downstream
Attainable Net Data Rate:         6596 kbps            26344 kbps
Actual Aggregate Tx Power:           6.0 dBm             11.1 dBm
====================================================================================
      VDSL Band Status     U0      U1      U2     U3     U4     D1     D2     D3
  Line Attenuation(dB):    8.8     48.8     N/A    N/A    N/A   21.1   61.1   90.3   
Signal Attenuation(dB):    8.8     48.2     N/A    N/A    N/A   29.6   60.7    N/A   
        SNR Margin(dB):    5.8     5.8      N/A    N/A    N/A   9.8    9.7     N/A   
         TX Power(dBm):   -4.9     5.7      N/A    N/A    N/A   8.8    7.4     N/A   


Kind regards,
Walter

[Chrysalis]

if the isp is advertising some kind of "fast as your line can handle" service you can argue they in breach, and withold payment.

even if they cut you off they still liable to BTw for 12 months so that wont be their preffered outcome, it may push thenm to cooperate, although I would try polite avenues first.

[waltergmw]

@ Chrysalis,

Just to clarify, there is no suggestion currently that the ISP is attempting to ignore the request.

They say, and I believe them, that they don't see any banding figures nor can they (yet ?) see the higher upstream rate figure.
I am hoping that is because the VDSL line is still within its official training period.

I observed a quite dramatic sync speed improvement immediately at power-up after the bridge tap condition was removed.
I would normally have expected increases in the bearer speed after a delay.
Again I suspect, because of the active training period, it means the service is still open to adjust as it wishes immediately during the modem / DSLAM sync process.

Kind regards,
Walter

[Chrysalis]

VDSL doesnt have a training period.  Its a myth been sourced from someone/somewhere for unknown reasons.  From day 2 onwards all FTTC lines under openreach are under constant line management, its not a temporary training period.  They also start off as fast as possible, its not slow working its way up, its the other way round.

so the question is does the line still sync at just below 20mbit with a much higher attainable when you reboot it?

if yes, DLM is holding it back. As there is only one thing that will cap a line at 20mbit given there is no 20mbit FTTC product.

[waltergmw]

Thanks Chrysalis,

The BT Wholesale estimator states:-

For all ADSL and WBC Fibre to the Cabinet (FTTC) services, the stable line rate will be determined during the first 10 days of service usage.


So I think I have to play the waiting game before starting another enquiry.

Here's the latest performance data I have showing an up time of just over 25 hours:-

Max:   Upstream rate = 6204 Kbps, Downstream rate = 24688 Kbps
Bearer:   0, Upstream rate = 6771 Kbps, Downstream rate = 19998 Kbps

Link Power State:   L0
Mode:         VDSL2 Annex B
VDSL2 Profile:      Profile 17a
TPS-TC:         PTM Mode(0x0)
Trellis:      U:ON /D:ON
Line Status:      No Defect
Training Status:   Showtime
      Down      Up
SNR (dB):    9.1       4.9
Attn(dB):    26.3       0.0
Pwr(dBm):    10.7       5.8
         VDSL2 framing
         Bearer 0
MSGc:      26      26
B:      237      207
M:      1      1
T:      37      40
R:      16      0
S:      0.3780      0.9754
L:      5376      1706
D:      1      1
I:      254      104
N:      254      208
         Counters
         Bearer 0
OHF:      50600906      1008734
OHFErr:      6580      165
RS:      1872223007      2340538
RSCorr:      1018441      0
RSUnCorr:   94023      0

         Bearer 0
HEC:      64929      0
OCD:      5683      0
LCD:      5683      0
Total Cells:   2532553886      0
Data Cells:   15833023      0
Drop Cells:   0
Bit Errors:   0      0

ES:      1805      179
SES:      22      22
UAS:      58      48
AS:      177607

         Bearer 0
INP:      0.00      0.00
INPRein:   0.00      0.00
delay:      0      0
PER:      3.50      9.79
OR:      72.93      26.14
AgR:      20071.01   6797.44

Bitswap:   118874/119699      13711/13738

Total time = 1 days 1 hours 21 min 16 sec

Kind regards,
Walter

[RealAleMadrid]

It appears that the line has been banded at 20Mbps, surely the ISP should be able to see what profile has been applied to the connection. The 10 day training period for FTTC has been shown to be a total myth, DLM kicks in after a couple of days and speeds generally go South after that. Best of luck to get the banding removed. 

[Chrysalis]

walter I think that message is just there to hold complaints off, they probably dont want to investigate unstable lines that they think DLM capping will mask the issue within the first 10 days stopping the callouts.

Its not like sky where they start slow and speed it up to come to a line speed, the line starts off uncapped (to product spec) and then will be slowed down if unstable.

Obviously DLM may remove the banding now the physical issue is resolved but thats nothing to do with that so called 10 day training.

Adsl did have a MSR, maximum stable rate, which is nothing to do with line training but rather at the end of the 10 days a MSR is calculated as a reference point for line capability.  As far as I know MSR was scrapped for FTTC services.  It may have bee reintroduced but even if it was it isnt to do with line training but more to do with recording a stable rate.

[waltergmw]

Thanks Chrysalis,

I have shown the figures illustrated here but currently the ISP has stated that they can't see any cap, rate banding etc. so are unable to act !
They also say (correctly) that the cct is now exceeding their Range B figures anyway, after we had removed the star wiring.

The BT Group, be it Openreach or Wholesale, must have DSLAM data similar to the HG612 data we observe.
I have to assume that only the bearer data is available to the ISPs ?

I have another two days to go before the "excuse" has expired so I plan to have another go then.

Kind regards,
Walter

[Chrysalis]

If your isp cannot see a cap on the data you shown in this forum then they are either incompetant or playing dumb.

In regards to what isp's see, plusnet do get banding info when they run line tests.  I assume all isp's should get the same data when they run line tests.

You can ask the isp to run a line test and show you the full results uncensored.  I think the test has a specific name, if anyone knows what it is it may help to ask for the test by name.

From where I sit the isp is probably mostly concerned about potential engineer callout fee's.

[waltergmw]

Gentlefolk,

Just to keep you informed Zen have now confirmed that they can see the profile is fixed at 20 Mbps "Because DLM observed a poor quality line. This should auto-correct within a week !!! "

More worrying is that Zen only quote THEIR B range estimate figure, BUT the public BT Wholesale figure shows a maximum B range of 21.2 Mbps. However Zen quoted their B range value of 19.5 which they obtained at order time.
N.B. at NO TIME are the A range figures even mentioned (except if you order a BT retail service direct).

In these circumstances Zen are obliged to order, after customer approval, an Openreach visit at £184.00 just to get the DLM reset manually.

Kind regards,
Walter

[Chrysalis]

Walter is up to you, but from your story it seems to be this fee 'may' need to be waived.

As I understand it an engineer is required to do a DLM reset under normal procedures, but an engineer cannot call in for a reset unless he changes something on the line.
On the previous visit a physical problem got fixed by a previous engineer but he didnt call in for a reset, so the new engineer shouldnt be billed for as this is an extension of that fault.  If zen get billed by openreach that shouldnt be your problem but their's to deal with.

Things change a bit tho if it was you or someone else outside of a openreach visit that fixed the wiring issue and in that case you probably going to have to wait it out to see if DLM raises the band, it may not do tho as I have seen bands stick.  Even if you paid for the visit a engineer probably wont do a reset if he finds nothing to change on the line.

[Black Sheep]

Chrysallis makes a good point about a non-Openreach repair, and subsequent DLM recalculations.

As with all things BT they have their guidelines, and it does indeed state on FTTC repair tasks not to perform a reset unless a fault has been found and rectified. But, I have a brain in my napper and feel being over 18yrs of age I can make my own decisions as to the best way to go about faulting a circuit.

So (in a nutshell), upon receipt of a FTTC task I look at the 28-day history via RRT. If it shows a lot of DLM activity like re-banding/interleaving every day in the small hours, then I will 're-calc' (reset) the circuit as the chances are the errors are being masked with the level of banding applied.
If when I view RRT there are lets say just two DLM events, with hardly any difference, then I wont perform a 'recalc' as the issue is likely to be something else other than speed related ?

The reason IN MY OPINION that the wording about resetting the circuit is applied to tasks, is that certain individuals were taking the easy route and only doing a reset. On the face of it to the EU, the fault has been repaired ........ we of course know better.

[waltergmw]

Gentlemen,

Thank you. This is definitely a case of tangled webs we weave !

This whole matter arose because the installing engineer failed to observe a bridged tap / star wiring, which I think "in the old days" would have caused the install to be abandoned.

In investigating the very poor performance, immediately after installation, a bridged tap was obvious. That caused us to investigate the slave socket installed by a previous occupier and then to disconnect it.

In the circs I have to hope I can believe in Zen's approach initially, but if DLM doesn't react, my next ploy will be to argue that the installation engineer failed (due to extreme and unreasonable work-load pressure) to test the VDSL performance.

UK PLC is paying the price for cost-cutting activities which, over time, are sadly degrading much of the communications infrastructure. In this case a possible "Up to 80 Mbps" started with a poor performing under 15 Mbps service - now improved to a better 20 Mbps; but where do we go next year when this user will undoubtedly be seeking at least the EU minimum ?

Kind regards,
Walter

[Black Sheep]

I've never known a job to halt on evidence of a 'Bridged Tap' ........ yesteryear or current day ??. We remove it whilst on-site, or if it's been 'over-looked' the DLM will just act accordingly, as in your case.

The problem with self-diagnosis and retrospective repair, is what you are seeing now Walter. You have done a fine job, but the red-tape ensures you will NOT see an immediate effect.
Also, even though a bridged-tap has obviously been found, I don't think OR would just take your word on it I'm afraid ?? Whoever did the install (OR or Contractors) should have performed at least one of our expected line tests to log baseline values. These would probably have recorded a high initial value due to DLM not having acted on the bridged-tap at that stage.

Also, (and I'm with everyone on the subject of crap workmanship), OR should at least have the opportunity to return and rectify the issues, either under the guise of a 'Repeat Report' against the circuit, or an 'Early Life Failure' if the circuit is relatively new, or via the complaints procedure known as 'e-Vipers'. This not only ensures a 'recalc' will be performed after the repair, but also leaves an audit trail for possible future issues that may need Ofcom inclusion.

It's only a pair of crappy wires, but procedures are everything I'm afraid. 

[waltergmw]

Thanks BS,

Perhaps my memory is slipping but I thought a few of the early installations did not go ahead immediately if house wiring was incompatible ?

The problem in this case is that Zen are claiming that the line's performance is reasonably close to their estimate at purchase time so we are promised / threatened with the £184 rectification charge. Although I've noticed that visiting BT Openreach engineers approach these matters with a good degree of common sense, the additional charge is enough to disturb many EUs.

Now on to a possibly more serious matter at an Elstead exchange VDSL installation by a Quinn engineer last Friday.
Being of a cautious nature with VDSL installations, I had recorded the then current ADSL performance which showed SN Margin up / down of 6.2 / 1.4 dB which was confirmed after a power reset with my 2Wire 2700 HGV giving Mgn 2 figures of 6.0 / 2.8 dB.

I requested that the engineer did a pair quality test but was told they have their own VDSL test equipment incapable of any other function.
(It turned out to be a Siemens tablet into which the engineer entered our Wireless password; I assume that means they have a web interface into the FTTC DSLAM data; although just conceivably they might access the ECI Port 1 modem directly.)

Once the installation work was completed the ECI DSL LED lit confirming sync.
I think, as an engineer escape plan, I was then told I had to contact Technicolor as our router wouldn't authenticate as it had been used on the ADSL service before.
Fortunately I was able to demonstrate the standard factory reset button which then allowed authentication completion.
At that time the engineer recorded a screen shot of numeric data on his tablet but tried to hide it from me.

(I was not best pleased to hear an F word as he left the house so I instructed him not to swear.
Instead of an apology I was told he was talking to himself ! )

Even though in this case we have remarkably good performance figures for a line of 1.15 km, excluding pole and pit loops, I am VERY UNCOMFORTABLE that the contractor acceptance procedure only relies on an immediate set of VDSL stats long before DLM can function and without any pair quality tests.
This might seem like a smart move by BT's accountants but must surely be contravening trading standards and Ofcom regulations ?
These matters are almost certainly way beyond most EU's technical comprehension.
Is it really right and proper that the "up to" 10/40 or 20/80 figures can so easily be used deceive the EU into a blind acceptance without any line performance check ?

Kind regards,
Walter

Here's the first set of readings after DLM has acted:-

Retrain Reason:   1
Last initialization procedure status:   0
Max:   Upstream rate = 8366 Kbps, Downstream rate = 40508 Kbps
Bearer:   0, Upstream rate = 8374 Kbps, Downstream rate = 35236 Kbps

Link Power State:   L0
Mode:         VDSL2 Annex B
VDSL2 Profile:      Profile 17a
TPS-TC:         PTM Mode(0x0)
Trellis:      U:ON /D:ON
Line Status:      No Defect
Training Status:   Showtime
      Down      Up
SNR (dB):    6.3       6.0
Attn(dB):    26.5       0.0
Pwr(dBm):    12.8       5.4
         VDSL2 framing
         Bearer 0
MSGc:      18      26
B:      51      239
M:      1      1
T:      64      44
R:      12      0
S:      0.0470      0.9108
L:      10904      2108
D:      689      1
I:      64      120
N:      64      240
         Counters
         Bearer 0
OHF:      1689825      508917
OHFErr:      2      0
RS:      432511185      906661
RSCorr:      175573      0
RSUnCorr:   9      0

         Bearer 0
HEC:      3      0
OCD:      0      0
LCD:      0      0
Total Cells:   345395272      0
Data Cells:   2473      0
Drop Cells:   0
Bit Errors:   0      0

ES:      9513      9
SES:      263      0
UAS:      56      45
AS:      5098

         Bearer 0
INP:      3.00      0.00
INPRein:   0.00      0.00
delay:      8      0
PER:      3.01      10.05
OR:      63.64      25.45
AgR:      35300.10   8399.19

Bitswap:   4035/4035      93/93

Total time = 1 days 16 hours 34 min 22 sec
FEC:      175573      0
CRC:      2      0
ES:      9513      9
SES:      263      0
UAS:      56      45
LOS:      1      0
LOF:      10      0
LOM:      0      0
Latest 15 minutes time = 4 min 22 sec
FEC:      16169      0
CRC:      0      0
ES:      0      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Previous 15 minutes time = 15 min 0 sec
FEC:      24206      0
CRC:      0      0
ES:      0      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0
Latest 1 day time = 16 hours 34 min 22 sec
FEC:      175573      0
CRC:      2      0
ES:      5714      4
SES:      187      0
UAS:      32      21
LOS:      1      0
LOF:      10      0
LOM:      0      0
Previous 1 day time = 24 hours 0 sec
FEC:      0      0
CRC:      0      0
ES:      3799      5
SES:      76      0
UAS:      24      24
LOS:      0      0
LOF:      0      0
LOM:      0      0
Since Link time = 1 hours 24 min 57 sec
FEC:      175573      0
CRC:      2      0
ES:      2      0
SES:      0      0
UAS:      0      0
LOS:      0      0
LOF:      0      0
LOM:      0      0


HELLO HG612
xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason:   1
Last initialization procedure status:   0
Max:   Upstream rate = 8358 Kbps, Downstream rate = 40380 Kbps
Bearer:   0, Upstream rate = 8374 Kbps, Downstream rate = 35236 Kbps
Discovery Phase (Initial) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3970)
Medley Phase (Final) Band Plan
US: (7,32) (871,1205)
DS: (33,859) (1216,1961)
     VDSL Port Details        Upstream        Downstream
Attainable Net Data Rate:        8358 kbps          40380 kbps
Actual Aggregate Tx Power:          5.4 dBm           12.8 dBm
====================================================================================
  VDSL Band Status        U0    U1    U2    U3    U4              D1      D2      D3
  Line Attenuation(dB):    9.0    48.0     N/A     N/A     N/A    21.3    58.9    88.6   
Signal Attenuation(dB):    9.0    47.5     N/A     N/A     N/A    29.9    58.5     N/A   
   SNR Margin(dB):         6.0    6.0     N/A     N/A     N/A    6.2    6.2     N/A   
    TX Power(dBm):        -5.7    5.0     N/A     N/A     N/A    11.2    7.8     N/A