2 mth fibre install suddenly loses sync then big speed drop

Hello everyone.

On 10 Mar 2014 BTw contractor arrived and unpacked an ICL modem then left. Speed tests confirmed my download was around 16Mb and my upload was around 2.25Mb. For 2 months after the install everything worked the same, day or night then on Sunday 11 May the modem lost sync.

An engineer from BTw arrived Monday afternoon and swapped out the modem for a Huawei which also would not sync, he replaced that with my modem then he went to the cabinet and from there he phoned me to see if the modem was syncing which it was, but my LAN was knocked out. The engineer came back to the house and changed the modem again for the Huawei. It synced right away (the modem light went solid) and he left

Speedtests showed that my speeds had taken a hit and I was getting around 10Mb down and around 0.5Mb up. I spoke to Zen, my ISP who said that the line looked like it had never managed the speed I was quoted and they would ask BT to send out another engineer.

He arrived on Wednesday 14 May about 9am and said he could see errors on the line. He went 200 metres down the road to a manhole and spend four hours with a colleague to no avail. He said the only spare pair was longer than mine and its speeds being worse there was nothing else he could do. There was some condensation and he had cleaned that up so had fixed the errors he was seeing but that was all the speed the line was able to deliver.

My ISP phoned again yesterday afternoon to say that there was definately a fault and they would escalate it with BTw. The line had held a 2.25Mb upload for 2 months, clearly something was wrong, and they would definately be pressing BTw to fix the problem as they could guarantee a minimum of 2Mb upload. An appointment was booked again for an engineer to visit tomorrow Friday the 16 May in the morning.

I little while ago Zen called again to say that should the engineer not be able to fix the problem and this was a third visit then the engineer would need to log the fault as a clear code so that my service could be cancelled so that we wouldn't go round in circles sending out engineers.

What would you do in my position ?

Have I posted this thread in the wrong forum ?

Zen forum is here http://forums.thinkbroadband.com/zen.html

Thanks, however I do not think Its a Zen specific problem, I only mentioned them.

Edited by deleted (Sun 18-May-14 17:37:01)

I dont know, you stuck in a hard place.

Its possible a distruber pair had vdsl activated and this is crosstalk, in which case you screwed if the only spare pair is worse.

However if its crosstalk (which supposedbly affects long lines less) then a drop you have reported seems very large. Especially on the upload.

There is escalation procedures that zen should be able to follow. So an idea is to ask zen to escalate it. I am reffering to the HLE's

https://www.btwholesale.com/pages/static/Application...

Speed boost engineer arrived on Friday 16th May. Spent all day here and after changing/replacing what he could there was little difference to attainable speeds. He said the line I was on is probably already the best one. He also performed a lift and shift and spoke to his help desk for a bit. However due to the lift and shift the help desk now had nothing to look at (so they said - where is the log from the port I was on ?) End result of the visit is the engineer telling me there are no faults on my line and any other engineer visits will likely incur a charge. (Zen since said they would contest the charges and not to worry, should they feel the need to send out another engineer).
Zen escalated this to HLE who have since said they where not willing to take on the case. My ISP are now pushing for me to make a decision about keeping the line or not.

What is eating at me is why my upstrean sync rate is slower than it was when I was connected to the exchange and not to a cabinet which is much closer (the cabinet is less than half the distance to the exchange). My attainable speed is now DS 14128kbps and US 890kbps. If I power cycle or reboot the modem, it never syncs at 890 always much lower even when my SNRmargin is sitting as high as 7.2dB (upstream).

I have since installed an unlocked hg612 and can see my stats, but that is now and not before the fault. Is someone (better than me) able to take a little time and look over what stats I now have if I where to post them somewhere. My gut tells me something is wrong but my BTo are saying that is all the line can and will ever support (however it has since jumped from DS 10Mb to 14Mb and US 0.5 to 0.7) despite previous speeds before the fault.

Your a better person than I if you can figure this out for me.

Thanks in advance.
Stuart

Edited by deleted (Tue 10-Jun-14 14:12:54)

What's ADSL like where you are.... No way would I pay for "fibre" and get any speed below 30mbps.

If your close to the exchange then wouldn't it be worth getting an ADSL connection instead as it may give similar speeds for a lot less the price...

It seems like you aren't going to get any help with this if Zen are offering to cancel the line.

I'm also assuming that Virgin Media is not available either.

ADSL speeds last sync before changing where DS 9367 kbps US 1075 kbps with SNRM of 6.0. My DS attenuation was 44.5 and US attenuation was 25.6. So I would guess at around 3 KM from the exchange.

I was with adsl24 who changed to Coms and they used Talk Talk for the LLU and my upstream speeds dropped to 443 kbps with Coms.

I was paying around £30 a month with adsl24 and allowed 45 Gig peak traffic (up and down) so at least I am saving £3 lol. I also have unlimited usage with Zen, so the family can watch Iplayer now during the early evening.

I value the support I could/can/have had from Zen, not having to deal with Indian call centres.

I'm just gob smacked that my US attainable speed appears to have dropped so much almost over night.

My plan at the minute is to (try) leave the connection alone for a few weeks.

No Virgin here. I had that when I lived in East Kilbride up until 7 Years ago. I was an early adopter with BlueBlunder (sorry Yonder) when it was a 512/128 kbps service (It was better then in some ways).

I live in South Ayrshire now and it is semi rural near Prestwick airport My exchange is also Preswick.

Edited by deleted (Tue 10-Jun-14 20:34:07)

If I was in your shoes I would switch my line to plus.net ADSL and as they are using BTw network then you could get better than you used to (downstream attenuation)

But its if the difference in speed and price really matters to you.

I'm not so sure I would like plus net. I like being a part of Zens smaller family. Cost wise I do not have a problem. It was worse on ADSL (see post above)

Well then it seems that the lines in your area are of very poor quality.... I'm not sure if I asked this already but is Virgin Cable available to you?

The lines are aluminium but they served me very well on ADSL for 2 years and as I said solid for 2 months on VDSL. It doesn't explain (to me anyway) why my sync speed went from DS 2000 kbps to 500 kbps overnight.

No cable in my area (see my post 2 above)

Here are some stats

xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 810 Kbps, Downstream rate = 13972 Kbps
Bearer: 0, Upstream rate = 738 Kbps, Downstream rate = 14171 Kbps

Discovery Phase (Initial) Band Plan
US: (6,31) (882,1193) (1984,2770)
DS: (33,857) (1218,1959) (2795,4083)
Medley Phase (Final) Band Plan
US: (6,31) (882,1193)
DS: (67,857)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 810 kbps 13972 kbps
Actual Aggregate Tx Power: 5.9 dBm 8.3 dBm
====================================================================================
VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 7.8 65.6 61.7 N/A N/A 27.0 82.5 N/A
Signal Attenuation(dB): 7.8 61.4 N/A N/A N/A 31.0 N/A N/A
SNR Margin(dB): 6.2 6.1 N/A N/A N/A 6.2 N/A N/A
TX Power(dBm): 1.8 3.8 N/A N/A N/A 8.3 N/A N/A
#

xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 803 Kbps, Downstream rate = 13924 Kbps
Bearer: 0, Upstream rate = 738 Kbps, Downstream rate = 14171 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): 6.1 6.0
Attn(dB): 29.8 0.0
Pwr(dBm): 8.3 5.8
VDSL2 framing
Bearer 0
MSGc: 26 34
B: 239 22
M: 1 1
T: 42 17
R: 0 0
S: 0.5381 0.9684
L: 3568 190
D: 1 1
I: 240 23
N: 240 23
Counters
Bearer 0
OHF: 18377039 217242
OHFErr: 631 103
RS: 0 1011641
RSCorr: 0 0
RSUnCorr: 0 0

Bearer 0
HEC: 1889 0
OCD: 222 0
LCD: 222 0
Total Cells: 2834416176 0
Data Cells: 85440725 0
Drop Cells: 0
Bit Errors: 0 0

ES: 390 94
SES: 0 0
UAS: 21 21
AS: 104241

Bearer 0
INP: 0.00 0.00
INPRein: 0.00 0.00
delay: 0 0
PER: 5.67 16.52
OR: 45.13 19.36
AgR: 14216.46 757.04

Bitswap: 62986/62987 66/70

Total time = 1 days 4 hours 57 min 42 sec
FEC: 0 0
CRC: 631 103
ES: 390 94
SES: 0 0
UAS: 21 21
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 12 min 42 sec
FEC: 0 0
CRC: 3 1
ES: 3 1
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 0 0
CRC: 1 1
ES: 1 1
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 4 hours 57 min 42 sec
FEC: 0 0
CRC: 85 18
ES: 50 17
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 0 0
CRC: 546 85
ES: 340 77
SES: 0 0
UAS: 21 21
LOS: 0 0
LOF: 0 0
LOM: 0 0
Since Link time = 1 days 4 hours 57 min 19 sec
FEC: 0 0
CRC: 631 103
ES: 390 94
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
#

Edited by deleted (Tue 10-Jun-14 23:13:24)

You said your using a HG612 thats unlocked right?

If so is there an option for it to use VDSL1 only and not VDSL2 as this may help get more speed and stabilise the line due to it using lower frequencies that won't be affected by much if any crosstalk.

you got further than I did with plusnet, plusnet only sent out SFI engineers and said they had no speed boost engineers at all for FTTC, no idea if they were been honest or not with me. In my case any work I requested was rejected by engineers. Eventually I got sick of it and stopped the engineer appointments.

There is no seeable option to use VDSL1 off the top of my head

# xdslcmd profile --show

Modulations:
G.Dmt Enabled
G.lite Enabled
T1.413 Enabled
ADSL2 Enabled
AnnexL Enabled
ADSL2+ Enabled
AnnexM Disabled
VDSL2 Enabled
Phone line pair:
Inner pair
Capability:
bitswap On
sra On
trellis On
sesdrop Off
CoMinMgn Off
24k On
phyReXmt(Us/Ds) Off/On
TpsTc AvPvAa
monitorTone: On
dynamicD: On
dynamicF: Off
SOS: On
Training Margin(Q4 in dB): -1(DEFAULT)
#

I'm also dubious that VDSL1 would have the reach if I am over 1500 metres from DSLAM (just thinking out loud).

Post deleted by scotsmist

In reply to a post by Chrysalis:

you got further than I did with plusnet, plusnet only sent out SFI engineers and said they had no speed boost engineers at all for FTTC, no idea if they were been honest or not with me. In my case any work I requested was rejected by engineers. Eventually I got sick of it and stopped the engineer appointments.

That's about where I am at. The BTo engineers have stated nothing can be done to the line. Yet IMHO something has changed. Perhaps the modems power output ?

Edited by deleted (Tue 10-Jun-14 23:57:24)

Might be something we could both do with looking into...

I can't see it being impossible, It would be like the days of switching ADSL2+ back to ADSL1

I'm thinking it is the DSLAM that sets what modulations are available and I do not see ITU G.993.1 or VDSL in the modulation list displayed by xdslcmd profile --show I posted above.
I'm also thinking that my line is too long for any VDSL frequency and can only get upto ADSL2+ frequencies. I just regret not keeping my logging after VDSL was first installed when I had DS 17700 kbps and US 2742 kbps for the first 2 weeks.

all I can think of at the moment then is getting in touch with zen and see if they can get it swapped to see if it will work..

I understand your concern about line length and (a shot in the dark here) maybe it will increase the power on the line that on higher frequencies would decrease bandwidth though on lower (8mhz) frequencies it might work...

Unfortunately I don't have FTTC or even access to it so I can't try anything myself.

I hear what your saying about increasing power on lower frequencies and this is where I need more bits per tone. I have a huge gap in my tones from around 1380 - 2070 kHz and no idea yet why as that is on my downstream and my own concern at the minute is the upstream.

I do not understand why after a reboot the modem can show higher power levels on band U0 and lower on U1 than a previous boot and hence more tones at the higher frequencies have bits loaded.

I also find it strange that my line attenuation on band U1 is higher than U2 and yet my signal attenuation on U1 is lower than my line attenuation at U1 but signal attenuation at U2 is N/A (unless my signal attenuation at U2 is higher than my line attenuation at U2). Hope that made sense. Could/does the DLM artificially raise the signal attenuation to cut back power ?

what modems are and have you used with this connection and do you know the manufacturer of your NGA?

I know the HG612 is supposed to be the best, but maybe if your NGA is ECI then the ECI modem might work better....

Also you can't guarantee that the modem your using is working correctly.

I have an ECI (locked) and 2 HG612 unlocked modems that give very similar results.
I believe (looking at pbParams posted above) that I am on an ECI at the cabinet.

The down side of course with the ECI modem is no stats to see if its better or worse. The HG612 I use is the one which gives best stats but there really wasn't that much between the two Hueweui's and the one I use gives a slight better attainable but only by a few bits. I haven't tried different firmware though but don't (yet) see that as a major player.

I need to hit the sack, its getting late. Cheers for now.

Edited by deleted (Wed 11-Jun-14 01:34:57)

Ok well you have eliminated that then...

The only other thing I can say is you got lucky for 2 months and the speed your line "can" actually support is what your getting now...

A friend of mine who is also on here has had his FTTC for 2-3 weeks now and at first he was getting 78/20 and very good latency and connection but then it it started dropping and dropping and still is now.. (He's currently synced at (63/20 and a low latency profile has been added to his downstream)

He also has aluminium in his line, but it is a short line with just 150-250m between him and his NGA (including to PCP)

Also with your area being non cable I would assume that FTTC take up on your cabinet and area has been rather heavy, and this may also be the issue with your speed.

Here is the output from pbParams note the increase in power levels and the highr attainable rate on the US. I know should I reboot the modem it will not sync at the higher rate, but instead it will reduce power levels and perhaps even sync slower.

xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 1007 Kbps, Downstream rate = 13660 Kbps
Bearer: 0, Upstream rate = 793 Kbps, Downstream rate = 13661 Kbps

Discovery Phase (Initial) Band Plan
US: (6,31) (882,1193) (1984,2770)
DS: (33,857) (1218,1959) (2795,4083)
Medley Phase (Final) Band Plan
US: (6,31) (882,1193)
DS: (67,857)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 1007 kbps 13660 kbps
Actual Aggregate Tx Power: 6.5 dBm 8.3 dBm
====================================================================================
VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 7.8 65.5 61.5 N/A N/A 27.0 82.7 N/A
Signal Attenuation(dB): 7.8 62.7 N/A N/A N/A 31.0 N/A N/A
SNR Margin(dB): 6.1 6.6 N/A N/A N/A 6.8 N/A N/A
TX Power(dBm): 1.9 4.7 N/A N/A N/A 8.3 N/A N/A
#

I hear you, but a 70% drop in attainable US over night once the modem was replaced is a bit of a sticking point for me. DS isn't my complaint at the moment, though it did drop from 16 Mb to 10 Mb also overnight, but I have seen that creep up as high as 14 Mb.

I also find it very unusual that a line as long as this one has no interleaving on it (afaik). I suspect BTo help desk have 'tweaked' something to try to increase the upstream but at the detriment of the downstream.

I was probably one of the last people on my cabinet, its in a semi rural area. I am probably also the furthest away from the NGC too. Not many houses around me, I am next to an airport runway so mostly the odd business and a few farms. When I spoke with the engineer on the 14th May (second visit) he said there where 2 cards in the cabinet and the one I was on had very few connections and there wasn't much calll here. The farm next to me has changed from ADSL to VDSL back in April and that had a little effect on my attainable speeds, but not too much (10-20% of next to nothing is still next to nothing) perhaps half a meg DS and a few hundred bits US (the farm's line is about 100m longer than mine). Its the sudden overnight loss of speed that is bothering me, not a gradual loss say due to increased cross talk etc. I still feel the modem is holding back power.

Edited by deleted (Fri 13-Jun-14 10:49:48)

xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 939 Kbps, Downstream rate = 14264 Kbps
Bearer: 0, Upstream rate = 795 Kbps, Downstream rate = 12619 Kbps

Discovery Phase (Initial) Band Plan
US: (6,31) (882,1193) (1984,2770)
DS: (33,857) (1218,1959) (2795,4083)
Medley Phase (Final) Band Plan
US: (6,31) (882,1193)
DS: (67,857)
VDSL Port Details Upstream Downstream
Attainable Net Data Rate: 939 kbps 14264 kbps
Actual Aggregate Tx Power: 5.9 dBm 8.3 dBm
====================================================================================
VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 7.9 65.6 62.3 N/A N/A 27.0 82.7 90.3
Signal Attenuation(dB): 7.9 59.2 N/A N/A N/A 31.0 N/A N/A
SNR Margin(dB): 5.7 6.3 N/A N/A N/A 6.8 N/A N/A
TX Power(dBm): 1.9 3.8 N/A N/A N/A 8.3 N/A N/A
#

xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 939 Kbps, Downstream rate = 14264 Kbps
Bearer: 0, Upstream rate = 795 Kbps, Downstream rate = 12619 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): 6.8 6.2
Attn(dB): 32.4 0.0
Pwr(dBm): 8.3 5.9
VDSL2 framing
Bearer 0
MSGc: 42 122
B: 51 53
M: 1 1
T: 64 1
R: 12 16
S: 0.1309 2.1236
L: 3912 275
D: 247 16
I: 64 73
N: 64 73
Counters
Bearer 0
OHF: 51468200 786936
OHFErr: 244 0
RS: 290927216 3211876
RSCorr: 236220 3042
RSUnCorr: 10741 0

Bearer 0
HEC: 1990 0
OCD: 281 0
LCD: 281 0
Total Cells: 1904629493 0
Data Cells: 437923663 0
Drop Cells: 0
Bit Errors: 0 0

ES: 135 0
SES: 0 0
UAS: 21 21
AS: 432800

Bearer 0
INP: 3.00 3.50
INPRein: 0.00 0.00
delay: 8 8
PER: 8.40 17.05
OR: 45.66 60.03
AgR: 12664.52 855.56

Bitswap: 204343/204475 40/42

Total time = 1 days 13 min 41 sec
FEC: 236220 3042
CRC: 244 0
ES: 135 0
SES: 0 0
UAS: 21 21
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 13 min 41 sec
FEC: 49 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: 245 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 = 13 min 41 sec
FEC: 49 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 40908 596
CRC: 25 0
ES: 15 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Since Link time = 5 days 13 min 19 sec
FEC: 236220 3042
CRC: 244 0
ES: 135 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
#

Note that Interleave is now on. Just before rebooting I noted that the attainable DS was 15000+ and US was 1300+
I bought a 0.5m twisted pair RJ11 cable from tandy online and swapped it out for the flat modem cable supplied by OR.
Having swapped the rj11 cable for the shorter one I noted that my DS attenuation changed from 29.8 to 32.4 and when I put the flat cable back on it returned to 29.8 I actually ordered 2 of the 0.5m cables (one for my mum) and tried it too with the same increase. Do you think this is because the attenuation is now being measured on a different frequency than the longer cable (perhaps the measuring frequency isn't available with the longer cable hence why another frequency might be being used and giving a different value - just thinking out loud).
I read somewhere on here (I think) somone else who had an increased attenuation with a shorter twisted pair cable was told that the DLM would sort that out in a few days, but nothing yet after 5 days.

Would anyone be interested in seeing charts of QLN HLog and SNR ?

Edited by deleted (Wed 25-Jun-14 11:38:18)

Here are some graphs taken 2 minutes ago

[img=http://s29.postimg.org/lyeznq11v/Bitloading_2014_06_25_12_19_53.png]

[img=http://s29.postimg.org/sqa04bff7/HLog_2014_06_25_12_19_53.png]

[img=http://s29.postimg.org/xq7gc9l1v/QLN_2014_06_25_12_19_53.png]

Edited by deleted (Wed 25-Jun-14 12:21:22)

Can you describe the line run from the modem to the cabinet? Pictures would be good.