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[frogfoot]

Hi,
I have been having a long running problem with my phone line and broadband.  It started in May, and I have had nine engineer visits, with most simply using their test equipment to run a test, saying all is fine and leaving.  Three have detected HR faults and replaced gel crimps, with one finding the DP was full of water. No-one has looked at the underground section of the line.

 Sadly none of the fixes have solved the underlying problem which manifests itself as an intermittent noisy crackly phone line and at the same time a drop in SNR and spike in errors. This often leads to one or more resyncs of the router.  Sometimes the broadband is down for an hour or more.   

Interestingly I have noticed that when the broadband is acting up, (lots of disconnections and very low SNR) I can sometimes temporarily fix it by making a phone call. Whereas sometimes the problem is initiated by an incoming call.
 

My sync speed has dropped from 80M to its current level of 67M which is not so much of a problem, but I'm worried that it will keep dropping.

I am 50yds from the cabinet, however for reasons best known to BTOR the line runs underground, past my house for 100yds then comes back overground to my house.  (The house opposite mine is fed from the pole directly outside my house, which gets its feed directly from the cabinet, so has a run of less than a quarter of mine.)


I've been logging stats since May (username frogfoot10). Unfortunately I have no logs from before the problem manifested itself to act as a baseline.

Hopefully someone may recognise the symptoms and give me some advice.
Cheers
Tom
 

[Ronski]

As this has been going on since May I would suggest a polite email to the CEO of Openreach explaining what's been happening, how many visits you've had and that it's still not resolved. With a bit of googling you should be able to find the appropriate email address.

https://www.openreach.co.uk/orpg/home/aboutus/ourorganisation/ourexecutiveteam/executiveteam.do

I'm no expert but it does sound like an HR fault.

[burakkucat]

. . . it does sound like an HR fault.

I concur. 

[frogfoot]

An update on this....

I wrote an email to Clive Selly and his team very quickly got in contact with me and assigned a 'complaint manager' and a dedicated engineer to sort the problem.

The engineer was very helpful and spend ages looking at the graphs on MyDSLwebStats today.  He immediately suggested running a new cable from the DP by the cab to my house,  reducing the cable run from 300m to 100m.  (I'm 50m from the cabinet and the distance between the cabinet and the DSLAM is 50 m)

Attenuation figures have dropped from 12.5db to 6db.

He performed a DLM reset and the modem resynced.  However there seems to be a ton of interleaving on the line,  Is this normal?  I was under the impression that after a DLM reset the modem would sync at its max attainable rate with no interleaving or INP applied, and then reduce the sync/ increase interleaving as required after a period of testing.

Weirdly the Quiet line test from the long cable run seems better than the new shorter run or am I misinterpreting the graphs.

Is it normal for a DLM reset to behave like this?  What could cause the lower QLN test results?

Code: [Select]

adsl info --stats
adsl: ADSL driver and PHY status
Status: Showtime
Last Retrain Reason:    0
Last initialization procedure status:   0
Max:    Upstream rate = 30901 Kbps, Downstream rate = 81103 Kbps
Bearer: 0, Upstream rate = 19999 Kbps, Downstream rate = 69439 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):        5.4             15.3
Attn(dB):        6.6             0.0
Pwr(dBm):        13.5           -11.2


                       VDSL2 framing

                        Bearer 0
MSGc:           18              26
B:              51              237
M:              1               1
T:              64              42
R:              12              16
S:              0.0238          0.3781
L:              21488           5374
D:              1359            1
I:              64              127
N:              64              254

                        Counters
                        Bearer 0
OHF:            4303995         1660221
OHFErr:         0               15
RS:             1101657151              69698473
RSCorr:         298             58
RSUnCorr:       0               0

                        Bearer 0
HEC:            0               0
OCD:            0               0
LCD:            0               0
Total Cells:    879869139               0
Data Cells:     36027088                0
Drop Cells:     0
Bit Errors:     0               0

ES:             0               13
SES:            0               0
UAS:            30              30
AS:             6590

                        Bearer 0
INP:            3.00            0.00
INPRein:        0.00            0.00
delay:          8               0
PER:            1.53            3.98
OR:             125.41          64.22
AgR:            69564.26        20063.54

Bitswap:        26/26           7/7

Total time = 1 hours 50 min 20 sec
FEC:            298             58
CRC:            0               15
ES:             0               13
SES:            0               0
UAS:            30              30
LOS:            0               0
LOF:            0               0
LOM:            0               0
Retr:           0
FailedRetr:     0
FailedFastRetr: 0
Latest 15 minutes time = 5 min 20 sec
FEC:            0               0
CRC:            0               0
ES:             0               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Retr:           0
FailedRetr:     0
FailedFastRetr: 0
Previous 15 minutes time = 15 min 0 sec
FEC:            0               13
CRC:            0               3
ES:             0               3
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Retr:           N/A
FailedRetr:     N/A
FailedFastRetr: N/A
Latest 1 day time = 1 hours 50 min 20 sec
FEC:            298             58
CRC:            0               15
ES:             0               13
SES:            0               0
UAS:            30              30
LOS:            0               0
LOF:            0               0
LOM:            0               0
Retr:           0
FailedRetr:     0
FailedFastRetr: 0
Previous 1 day time = 0 sec
FEC:            0               0
CRC:            0               0
ES:             0               0
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Retr:           0
FailedRetr:     0
FailedFastRetr: 0
Since Link time = 1 hours 49 min 49 sec
FEC:            298             58
CRC:            0               15
ES:             0               13
SES:            0               0
UAS:            0               0
LOS:            0               0
LOF:            0               0
LOM:            0               0
Retr:           0
FailedRetr:     0
FailedFastRetr: 0
NTR: mipsCntAtNtr=0 ncoCntAtNtr=0
 >    

[j0hn]

He performed a DLM reset and the modem resynced.  However there seems to be a ton of interleaving on the line,  Is this normal?  I was under the impression that after a DLM reset the modem would sync at its max attainable rate with no interleaving or INP applied, and then reduce the sync/ increase interleaving as required after a period of testing.

That's normal on Huawei cabinets

Weirdly the Quiet line test from the long cable run seems better than the new shorter run or am I misinterpreting the graphs.

I'm certainly no expert on QLN graphs, but the newer QLN looks better to me.

[burakkucat]

Weirdly the Quiet line test from the long cable run seems better than the new shorter run or am I misinterpreting the graphs.

The QLN (quiet line noise) plots have a couple of subtle differences --

• the "long" has more lower frequency RF ingress than the "short"
• the average noise floor of the "long" is lower than that of the "short"

However they are both perfectly respectable plots; neither should be the cause for any concern.

Shape wise, considering the overall flatness (having viewed each plot in a repeating sequence so as to take in every nuance), I prefer the "short" plot.

[frogfoot]

Thanks for the reply.  I'm not worried or complaining, just interested.   In fact I'm over the moon that BT has finally got rid of the old 'long' cable route as it has cause several problems in the last few years.    I was just interested that in several threads I've read that a good QLN should be -140db ish  whereas my noise floor hovers about 100db.  I wonder it there is a local source of wideband RF interference near the cabinet which could be causing interference on all FTTC connections in the village.  Or is there another likely explanation for a QLN on a very short, new line which is relatively high.
Cheers
Tom

[burakkucat]

It would be very difficult to say why the noise floor is elevated from around the preferred -140 dBm/Hz value without using a spectrum analyser and other such items of exotic test equipment. At best, I could suggest that it might be due to the level of the underlying wideband background "mush" in your particular environment and, with a better quality line, more of the wideband background "mush" is now being received.

I will suggest that you check how the circuit is behaving once per day and then review the situation in a month's time.