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[burakkucat]

PCP 51 is at the corner of Park Road (main road) and Heatherdale Avenue.

That satisfies the inquisitive cat. Thank you.

There is one option you could consider. Downgrade your package to 40/10. You would be paying out less per month and would probably obtain a throughput of 38/9 Mbps DS/US.

As you say in the subject header: "possible line fault". So far, you have not presented any concrete evidence -- only anecdotal memories. However, with a D-side pair length in the order of 450 - 500 metres, I would expect you achieve a better throughput than current. Hence I will agree that there may be a possibility to improve the pair's characteristics. 

[burakkucat]

I've just read this news item at ThinkBroadBand concerning the Openreach special offer of 80/20 FTTP being available in FTTC enabled areas.

My understanding is that a fibre is run from a fibre-splitter at the FTTC to the user's premises, thus doing away with the VDSL2 copper pair.

As a business user, perhaps that option may be worth considering? (If available in your area.)

[eliw]

That would be brilliant !

How can I find out if this available here ? The checker does not mention fttp at all.

Wouldn't that involve running a fiber line all the way up to us, thus digging up the road for just one customer ?

[burakkucat]

The best way would be to register your interest in the "on demand FTTP product, in FTTC enabled areas" (which is how, I believe, it is currently known within the BT Group).

As for physically getting the fibre feed to the premises, there are three main ways. Using existing underground ducting. Microtrenching a new underground feed. Using existing poles for an aerial feed. Every location will be different and the technique used would depend upon a site survey.

[eliw]

Btw I have decided to log a phone line fault on the BT site - not expecting much, I was very suprised to see a fault job number appear once I pressed "check my line" - I proceeded to check the progress of the fault on the site, the following messages are now displayed (I have since then received an SMS stating the date of the engineer visit to the exchange/cabinet and that it may require a visit to my property as well)



Is this encouraging ? or is it just standard procedure ?

[burakkucat]

Well not having actually been an employee of the BT Group nor a Business customer of BT Retail, I would be somewhat encouraged by that. At least you do have a job reference number linked to your line and, if needs be, you can use that reference number to haunt the "Evil Empire of Newgate Street". 

Perhaps Bald_Eagle1 will be able to advise you of the information that would be helpful to present to the attending engineer . . . 

[Bald_Eagle1]

Perhaps Bald_Eagle1 will be able to advise you of the information that would be helpful to present to the attending engineer . . . 

If you have been saving any terminal data logs, we might be able to put together a series of graphs that MAY highlight changes in conditions such as attenuation (Hlog), SNR, QLN, bit-loading.

Also, If you had enabled it via Maintenance, Log, Displaying Log, you might be able to report all the re-syncs that are probably NOT shown in any ISP logs:-

2012-3-25 9:31:7 Notice 104500 DSL activate succeed
2012-3-25 9:30:45 Notice 104500 DSL deactivate
2012-3-25 9:30:7 Notice 104500 DSL activate succeed
2012-3-25 9:29:11 Notice 104500 DSL deactivate
2012-3-25 9:27:9 Notice 104500 DSL activate succeed
2012-3-25 9:26:47 Notice 104500 DSL deactivate
2012-3-25 9:24:28 Notice 104500 DSL activate succeed
2012-3-25 9:24:12 Notice 104500 DSL deactivate


The best option is to use a combination of "snapshot" graphs & the 24/7 logging graphs as any changes can be seen graphically.
Engineers aren't allowed much time for each job so they wouldn't spend time looking at tables of data, but a picture is worth thousands of words/rows of data.

I would ask to see BT's Network Records that may identify sections of aluminium and the actual route to the actual cabinet.

It waould also be good to ask the engineer for the line length as reported from his JDSU or Exfo tester.
If it is reported as a lot more than the physical length, that would indicate "too much" attenuation.

Finally, depending on the type of engineer, it would be worth asking for a TDR test that should identify issues such as high resistance, tapped bridges, open circuit joints etc.

If this ends up being the first of a number of visits, you could always prepare "evidence" for the next visit.

Without "evidence" it may be difficult to force any furher action if nothing is found at the first visit.

EDIT:

My attached example graph set of a 30 day window is the only sort of hard evidence that is keeping my ISP in the loop after 10 months of ongoing intermittent issues.

I really have lost count of the number of times I have been told LTOK & "operating within acceptable limits".

I do have to thank Plusnet for not giving up on this.
It is just frustrating that it is impossible to get an engineer on site just when the "issues" are at their worst.

BTW, I have not been charged for any of the numerous engineer visits.

Let's hope that your issue can be clearly identified & rectified at the first visit.
From what you have reported here, it would appear that if there is indeed a "fixable" issue, evidence of it is present 24/7.

[eliw]

Thank you BaldEagle.

I don't suffer from any resyncs at all - in fact in the first 12 days (the modem was left on and untouched) there was not a single resync - and the Profile was pretty much at the top of the sync speed. It is when the IP profile was lowered that I started to get a bit inquisitive.

I have enabled the log feature on the modem (debugging mode) from day one and the only resyncs so far are when I rebooted it manually.

My only complaint is the fact that my sync speeds are low: 54 DS and 7 US, and maybe that my download profile is 10mbs lower than the sync speed which effectively gives me an up to 40 FTTC service for the price of the up to 80 service. The upload speed on my line, should be around 14mbs. All this of course considering that my line is less than 500 meters long.

[burakkucat]

. . . my line is less than 500 meters long.

Knowing both locations, I asked Google Maps to give me an estimate of the distance involved. Its response was ~0.4 mile.

[eliw]

I used a GPS plotter using my mobile phone (android app) while walking up the road from the PCP to my house. The distance was exactly 483m, you can't get more accurate than that. You basically press start measuring at the origin (the PCP) and then press end at the destination (my house) and you get the exact distance you walked +/- 10m for GPS approximation

... Maybe you are using the middle of the road. I'm at the closest end. Google maps showing 0.3mile for me.

[burakkucat]

... Maybe you are using the middle of the road. I'm at the closest end.

Indeed, I was. I just used the location Google Maps put the marker for the "GUnn nxyz" postcode. 

Now based on your very accurate measurement, one needs to add on a few metres for every underground joint chamber through which the pair passes and also if the line is finally delivered from an overhead DP, extra distance should be added for the climb "up the pole".

So perhaps we should say the pair length ~= 483 + 10 + (n x 2.5) + (p x 11) metres. [Where "n" is the number of joint chambers along the route and "p" is the number of poles involved.]

It would be very interesting to know what the pair length is determined to be when measured electrically with a JDSU, EXFO, Hawk or Mole and how it compares to the estimate, above. 

[eliw]

Yes indeed - really curious to find that out as well.

I recall calling a a special BT number (17070 ?) a few years back and it returned the length of the line (to the exchange) - does that number not apply to FTTC lines ? (oops just tried and it asked me for some authorisation number)

[burakkucat]

As you have discovered, the menu for the "magic" number (17070) has now been changed. The only option now open to normal mortals is number two, the Quiet Line Test.

Apparently the system was being heavily abused by certain sections of the public . . . The fools spoilt things for the considerate, occasional, users. 

I have re-measured the approximate route (Google Maps) using the latest information you have provided and it now reports 0.3 mile / 480 metres. Looking somewhat more closely at your end of the D-side cable, I see it travels up a pole on the north side of the road junction to reach the pole at the end of your road. So we definitely need to add about 11 metres . . . If you look at the pole on the north side of the junction, you should see the height cut into the wood. I will expect it to be 10, 11 or 12 metres. You will also need to walk the route and make a count of the joint chambers. as I can't do that from Street View.   

I suspect the grand total will be around 550 metres. 

[eliw]

Ok had a visit from the engineer today (Sunday) - out of the blue... I was suffering from a major hangover but still managed to show a little bit of cognitive attributes..

Anyway he was here in his telephony guise and as such was not gonna help me at all with the broadband side of things, but said that he did some broadband installs around here and he had certainly seen much higher DS/US from people with longer lines than mine, at which point I asked him if he could check what my line length was, but unfortunaly said he could not... 

He described the fault as generated by the online fault system as being a "a battery" on the line.. around 15V, so he went out to the pole just outside our house and started digging hammering and doing all sorts of noisy things... during all this time our line was down. It took him a good hour or so of intensive labour after which he walked back in and said that the fault was a lot more than the battery thing, he said he found the "joint" drenched in a pool of water so he replaced it (I think) and also put a new thing along the pole, some sort of a long black plastic box about 10 inches from the ground which looks a lot like an all weather junction box.

He then left to reconnect the line at the exchange (or the PCP) and came back within 10 minutes to test the line - first thing he said was that the line was perfect now as the resistances were equal on both wires, then he used a gizmo which he hooked up to the socket but unfortunately he could not run the tests as they were all coming back as failures despite him being sure that nothing was wrong anymore !? he insisted that his machine was knackered and that we could safely ignore it... he then left after telling me that I should get in touch with BT retail again and ask them to send a broadband boost engineer now that the line according to him was ok.

I reconnected the modem and the stats were still as before - no difference whatsoever. But just checked now a good 10 hours after the guy left and the attainable rate on the upload side has gone up by a good 1.2 megs (never moved from 8800 before today) but download attainable seems to have dropped by 1.5 megs tho lol

Now I am confused

Here are the new stats to compare with the ones I posted in my original message.

Code: [Select]

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max:    Upstream rate = 10450 Kbps, Downstream rate = 57032 Kbps
Path:   0, Upstream rate = 10000 Kbps, Downstream rate = 48007 Kbps

Link Power State:       L0
Mode:                   VDSL2 Annex B
VDSL2 Profile:          Profile 17a
TPS-TC:                 PTM Mode
Trellis:                U:ON /D:ON
Line Status:            No Defect
Training Status:        Showtime
                Down            Up
SNR (dB):        6.3             6.6
Attn(dB):        0.0             0.0
Pwr(dBm):        12.1            5.0
                        VDSL2 framing
                        Path 0
B:              34              118
M:              1               2
T:              64              48
R:              8               16
S:              0.0232          0.7545
L:              14829           2693
D:              1407            1
I:              43              127
N:              43              254
                        Counters
                        Path 0
OHF:            108880          26880
OHFErr:         0               0
RS:             41907013                1289653
RSCorr:         188             0
RSUnCorr:       0               0

                        Path 0
HEC:            0               0
OCD:            0               0
LCD:            0               0
Total Cells:    22525411                0
Data Cells:     1136910         0
Drop Cells:     0
Bit Errors:     0               0

ES:             0               0
SES:            0               0
UAS:            15              15
AS:             245

                        Path 0
INP:            3.00            0.00
PER:            2.22            9.05
delay:          8.00            0.00
OR:             86.21           54.77

Bitswap:        70              23

Code: [Select]

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max:    Upstream rate = 10454 Kbps, Downstream rate = 56900 Kbps
Path:   0, Upstream rate = 10000 Kbps, Downstream rate = 48007 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963)
       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:      10454 kbps         56900 kbps
Actual Aggregate Tx Power:        5.0 dBm          12.1 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB):  6.9     35.9    54.0     N/A    17.1    44.6    66.2

Signal Attenuation(dB):  8.9     35.2    51.8     N/A    17.1    44.6     N/A

        SNR Margin(dB):  6.7     6.6     6.5      N/A    6.3     6.2      N/A

         TX Power(dBm): -4.0    -6.9     4.1      N/A    10.2    7.8      N/A


[Bald_Eagle1]

Ok had a visit from the engineer today (Sunday) - out of the blue... I was suffering from a major hangover but still managed to show a little bit of cognitive attributes..

Anyway he was here in his telephony guise and as such was not gonna help me at all with the broadband side of things, but said that he did some broadband installs around here and he had certainly seen much higher DS/US from people with longer lines than mine, at which point I asked him if he could check what my line length was, but unfortunaly said he could not... 

He described the fault as generated by the online fault system as being a "a battery" on the line.. around 15V, so he went out to the pole just outside our house and started digging hammering and doing all sorts of noisy things... during all this time our line was down. It took him a good hour or so of intensive labour after which he walked back in and said that the fault was a lot more than the battery thing, he said he found the "joint" drenched in a pool of water so he replaced it (I think) and also put a new thing along the pole, some sort of a long black plastic box about 10 inches from the ground which looks a lot like an all weather junction box.

He then left to reconnect the line at the exchange (or the PCP) and came back within 10 minutes to test the line - first thing he said was that the line was perfect now as the resistances were equal on both wires, then he used a gizmo which he hooked up to the socket but unfortunately he could not run the tests as they were all coming back as failures despite him being sure that nothing was wrong anymore !? he insisted that his machine was knackered and that we could safely ignore it... he then left after telling me that I should get in touch with BT retail again and ask them to send a broadband boost engineer now that the line according to him was ok.

I reconnected the modem and the stats were still as before - no difference whatsoever. But just checked now a good 10 hours after the guy left and the attainable rate on the upload side has gone up by a good 1.2 megs (never moved from 8800 before today) but download attainable seems to have dropped by 1.5 megs tho lol

Now I am confused

Here are the new stats to compare with the ones I posted in my original message.

New pbParams:-

Code: [Select]

Max:    Upstream rate = 10454 Kbps, Downstream rate = 56900 Kbps
Path:   0, Upstream rate = 10000 Kbps, Downstream rate = 48007 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963)
       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:      10454 kbps         56900 kbps
Actual Aggregate Tx Power:        5.0 dBm          12.1 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB):  6.9     35.9    54.0     N/A    17.1    44.6    66.2
Signal Attenuation(dB):  8.9     35.2    51.8     N/A    17.1    44.6     N/A
        SNR Margin(dB):  6.7     6.6     6.5      N/A    6.3     6.2      N/A
         TX Power(dBm): -4.0    -6.9     4.1      N/A    10.2    7.8      N/A


I see there is a little improvement on signal attenuation across upstream band U0. Hence the higher US sync speed.
It looks like you are now in sync at the capped 10Mb upstream.

Nothing else stands out as having improved any.
Downstream Attenuation still looks "fairly" high for a line of relatively short length.

Also Downstream SNRM has no real "spare" capacity obove the target 6dB, so it looks like your connection is currently achieving more or less the maximum for the current physical line conditions.

This all suggests that there is possibly some high resistance, causing higher than "normal" attenuation levels.

Or, the line could actually take a longer route than both you & the engineer perceive at this stage.

Did the engineer mention aluminium cabling at all?

Finally, I suppose you could have a connection that is affected by noise interference, either permanently or in bursts of interference.

Maybe DLM has seen this & lowered your achievable sync speed profile (not IP Profile) to compensate.



Previous pbParams:-

Code: [Select]

Max:    Upstream rate = 8836 Kbps, Downstream rate = 58488 Kbps
Path:   0, Upstream rate = 8869 Kbps, Downstream rate = 48677 Kbps

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)
Medley Phase (Final) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963)
       VDSL Port Details       Upstream        Downstream
Attainable Net Data Rate:       8836 kbps         58488 kbps
Actual Aggregate Tx Power:        3.8 dBm          12.3 dBm
============================================================================
  VDSL Band Status        U0      U1      U2      U3      D1      D2      D3
  Line Attenuation(dB):  6.9     35.9    53.6     N/A    17.1    44.7    66.2
Signal Attenuation(dB):  10.3    35.1    51.4     N/A    17.1    44.7     N/A
        SNR Margin(dB):  6.2     6.1     6.1      N/A    6.4     6.7      N/A
         TX Power(dBm): -4.3    -7.1     2.5      N/A    10.5    7.6      N/A





If you could combine these into a single output file, or at a pinch into separate files, we could graph a snapshot of your connection that might give us all a clearer insight to its condition & comparison against other users' connections:-

xdslcmd info --pbParams
xdslcmd info --Bits
xdslcmd info --linediag
xdslcmd info --show
xdslcmd info --stats

The file(s) would be too large to upload to kitz unless you zipped it/them down to a smaller compressed size.


Just for future reference against a not so good connection, I have attached my graphs from when I rebooted the modem a few days ago.