FTTc install to present.

Hi. Just wanted to share with you.

I got my connection 40/10 installed on the 5th of June. Initial speed at about 650-700 m from cab was satisfying going from 3,5 on adsl to 37,4 on fibre (download). Ping was excellent at 6ms. Week later I got first indication that something was going on Pings up to 16ms and speed down to 33.

Since then..

It has been fairly stable in the meantime no drops and speeds + ping stayed solid in place. I have purchased hg612 also so I could monitor the line... This prompted me to further investigation. Although bt checker and tt estimate my line speed at around 36 I found various references to the speed possible of around 60meg at this distance from cab. Once with stats I could see my SNR going up and down like a yoyo (if I turned on tv + sky instatnly I lost 3meg of max attainable 41 down to 38) down to 4db and below. It was weird to see. I could also see some errors but dlm was not doing much with it so I thought to leave it and see wheather interleaving would get turned off. 7 days later nothing happened and fluctuation still occurs.

I have thought of the wiring in my house. As when the bt man came he did in fact move my master to another room thus extending the copper circut. At the time he had problems with getting signal in the newely installed socket. I thought at the time `hey you the expert so make it work` which he did in the end and went on his way. I always had a doubt tho. Has he done everything correctly as he should have? So today I have read an article about polarity.. Is it important which way around the cables connect? It never was on dsl is it on fibre?

Anyway I swopped the pair around and now my router shows snr of 8,2db (8,1 if i Turn on tv + sky) My max attainable went up from 39 today to 53 in an instant. Could the engineer cause my connection to not be set up correctly off the bat? Am I clutching at straws here and merely re-sitting the pair in the socket did the trick?

Oh and there is almost no errors whatsoever after over two hours of connection being up
I hope now dlm will turn this damn interleaving off also but I guess I will have to wait some time for this to happen.

Can someon please tell me if my interleaving depth is substantial or fairly small?

xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 16100 Kbps, Downstream rate = 53004 Kbps
Path: 0, Upstream rate = 9999 Kbps, Downstream rate = 39996 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): 8.2 11.0
Attn(dB): 0.0 0.0
Pwr(dBm): 13.3 7.6
VDSL2 framing
Path 0
B: 57 236
M: 1 1
T: 64 23
R: 16 16
S: 0.0461 0.7543
L: 12835 2694
D: 701 1
I: 74 127
N: 74 254
Counters
Path 0
OHF: 3473864 890122
OHFErr: 0 0
RS: 666981529 2279310
RSCorr: 1327 0
RSUnCorr: 0 0

Path 0
HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 593751450 0
Data Cells: 10520027 0
Drop Cells: 0
Bit Errors: 0 0

ES: 0 0
SES: 0 0
UAS: 22 22
AS: 7719

Path 0
INP: 3.00 0.00
PER: 2.21 8.67
delay: 8.00 0.00
OR: 86.72 59.02

Bitswap: 142 3

Total time = 2 hours 9 min 4 sec
FEC: 1327 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 22 22
LOS: 0 0
LOF: 0 0
Latest 15 minutes time = 9 min 4 sec
FEC: 422 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 2 hours 9 min 4 sec
FEC: 1327 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 22 22
LOS: 0 0
LOF: 0 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
Since Link time = 2 hours 8 min 39 sec
FEC: 1327 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0

Edited by deleted (Tue 26-Aug-14 19:39:24)

It looks like you've fixed it. DLM should relent within 10 days if you have.

In reply to a post by Kamil:

Anyway I swopped the pair around and now my router shows snr of 8,2db (8,1 if i Turn on tv + sky) My max attainable went up from 39 today to 53 in an instant. Could the engineer cause my connection to not be set up correctly off the bat? Am I clutching at straws here and merely re-sitting the pair in the socket did the trick?

Interesting as I'm just about to 'go' FTTC on a 600m line

You could always swap things back and compare stats - that will show you if it was just you making a cleaner connection or not.

I'd be a little worried if an 'engineer' struggled to get a connection after simply adding a data extension socket. It's hardly rocket surgery connecting two wires together.

If you do some reading around polarity, you'll note that it was important with legacy connections like dial up as equipment could be sensitive to it. By all accounts, it wasn't important with ADSL but, I've always made sure I observed the correct polarity whenever I've wired up a master socket.
Regardless of whether that was the cause of your issue, it seems as though you've fixed your problem. Good news!

Paul

Are you talking about swapping the actual pair coming in from the street?

I thought that we weren't allowed to touch these (and they carry voltage)...

Yes, I was referring to the 'drop wire'.

And yes again you are correct to a degree. 'Interfering' with the 'street' side of the master socket goes against the end users terms of service agreement with BTOR. In reality however, this would only cause an issue if a fault was raised and OR found it was the end users interference that caused it. The end user would then be liable for the OR call out charge.
OR are exceptionally unlikely to trace this back to the end user if all they did was remove, switch polarity and re-punch down the drop wire in the master socket. That being said, if you're not willing to accept the possible repercussions, you shouldn't interfere with the 'street' side of the cabling.

The wiring itself carries circa 50v DC. Enough to give you a buzz but, not threaten your life.

Paul

Edited by deleted (Wed 27-Aug-14 13:53:11)

Polarity is only important after the master socket, so no need to touch anything before it any way.

50V can kill and has done before. There is also 75v ring which certainly can give you a large kick.

In reply to a post by MHC:

50V can kill and has done before. There is also 75v ring which certainly can give you a large kick.

Its the volts that jolts but the mills that kills.
I recall reading of somebody being killed by falling on a 12v car battery, so hard that the terminals punctured the skin on his chest and the current stopped his heart.
I have had a nasty jolt from having my fingers in the wiring when a phone rang.

In reply to a post by b4dger:

You could always swap things back and compare stats - that will show you if it was just you making a cleaner connection or not.

I think I will leave it alone for a while and see if interleaving will get switched off

SNR staying at 8 so far so much better than previous fluctuation from 6 to 4. Max attainable still better by 12meg than previously.

Exactly my thoughts. He is an `engineer` and after rewiring my sockets he was getting no signal at all where I was previously using an adsl router so something was not right. he then proceeded to using a different pair and got signal. But even then I was asking him questions about fibre he was not very clued up about it I could not have an interesting conversation with him about the tech at all. Maybe he was having a bad day who knows.

And on a side note. My appointment was between 8-1pm. He never turned up on time and then I had to ring my provider for them to make sure that he was still coming. An hour and twenty minutes later a phone call..
He was coming after all. He said that my job only appeared on his thingy at around 1pm. How is that for organising the works at BTO.

There would be no way for me to prove a fault. The connection istelf was still decent enough and my gut feeling would not warrant a visit from bt. Just proves the point that sometimes the simplest solutions can make a huge difference. 5 minutes and one screwdriver + punch tool =

12-13 meg incresae in max attainable.
Sync up from 36-37 to 39996
SNRm up to above 8 from 4-6
Almost no errors

Two days later still nothing exploded so it might be alright

In reply to a post by Zarjaz:

Polarity is only important after the master socket, so no need to touch anything before it any way.

After master but before modem? How and where could this be done?

The polarity mentioned only affects telephony, and very rarely at that too. Faint faults on cordless phones, and constant bell ringing on older corded phones. This being due to an A/B reversal after the NTE.

So its possible that re-sitting wires did the trick then. Cheers

It could well be, maybe just poorly terminated by the engineer originally. Let's hope it all stays hunky dory from now on.

And by proxy, if it's incorrect before the master socket, it's likely to be incorrect after it...

How would you influence the polarity after the master socket, extensions excluded?

Paul

Edited by deleted (Thu 28-Aug-14 09:56:37)

Morning Kamil

I had a some-what similar experience many years back, when installing two DEC VT 102 Terminals, by "Current-Loop" to a DEC PDP 1/11 Computer.

Not identical though.

The CL Cable had two pairs of colour-coded insulated wires and one bare earth wire.

Works Engineering ran two cables in through the false ceiling void, to the far end of the mainly open-plan office, one terminating in that main area and the other in a private office almost immediately adjacent. So a lot of disturbance etc.

I terminated and connected the shorter cable, no problems of any sort.

But I just could not get the slightly longer cable to function, testing it for continuity etc - but limited in part by the distance separating the ends.

Fortunately, the office incumbent was not particularly keen to have a working terminal, so I gave up etc.

Some months later, that incumbent moved to a new job (Managing Director); and his replacement insisted on having a working terminal.

I tried for some time to get the cable to function - to no avail.

In desperation, I swapped over the two pairs of wires at the terminal end.

Hey Presto, IT WORKED.

Whilst some strange mix-up in the middle of that local cable run could explain the result,. I suspect that there was an inadvertent swap somewhere in the very much longer and convoluted run back to the Computer Room.

In reply to a post by Kamil:

Can someon please tell me if my interleaving depth is substantial or fairly small?

The depth is actually pretty irrelevant: Depth is a value negotiated by the modems in order to meet the requirements laid down by DLM. Those requirements are the things that are much more interesting.

DLM has set INP=3.0 and delay=8ms downstream, and nothing upstream. This is a fairly standard setting by DLM, usually used as the first attempt to improve quality/reduce errors. It shows that DLM has intervened, but it hasn't had to go further.

With these settings by DLM, the modems then choose (during sync negotiation) the interleaving depth & width (parameters D and I) to match these INP and delay factors... but you get to see the real impact in the form of the additional delay in the extended ping times (ie the 8ms).

Some other parameters negotiated by the modem also tell you more than the raw depth. The R and N parameters tell you how much FEC (self-correction) overhead is being used.

Downstream, you have 16 bytes out of every 74, or roughly 22% of your capacity. This is used to give the Impulse Noise Protection (INP) of 3.0 symbols when combined with the 8ms of interleaving.

Upstream, the modems have chosen to add 16 bytes of overhead in every 254 bytes, or roughly 6%. DLM has not asked for this protection, but it seems that modems often incorporate this during negotiation when there is spare capacity available. Note that this is just FEC protection upstream, but without any interleaving (D=1).

And by proxy, if it's incorrect before the master socket, it's likely to be incorrect after it...

The salient point being that polarity is only ever an issue on extension wiring, the polarity before the NTE matters not one iota*. The only thing that requires 'influence' is the termination on the extension socket, the polarity is was it is from the NTE's out put.






*There is a minuscule amount of earth calling lines running to VERY old PABX systems on which are polarity conscious. These lines are rarer than hens teeth these days.

It would probably annoy the hell out of if it happened to me! IBut it should work and everything is as it should then why isnt it :/ Sometimes the easiest and most irracional solution work and glad you got it in the end

WWWombat thank you very much for the explanation. Not that I understand it now... but I have better idea of what to look at in the stats in regards to interleave. Thanks for your time.

Do you not think it would have been more helpful to write that then? Instead of writing an ambiguous statement that looks to make another statement seem inaccurate? When it isn't.

The salient point is that if you're master socket exhibits the correct polarity, anything connected to it is also likely to, if installed correctly.

It seems the the first reaction on here is to attempt to discredit other members, instead of helping them!

Paul

It seems the the first reaction on here is to attempt to discredit other members, instead of helping them!

No attempt to discredit, just to inform.

Guys I have bit of an update. I have updated firmware on the router to the newest one. I did this on thursday 28th so two days after my initial post. I got 1meg increase in max attainable with rest of things staying pretty much as they were.

Then... a day later I started getting strange bursts of errors. Whenever I resynced I would get instantly few hundred fecs, few crcs and hecs. It did not matter which firmware I was using I tried a three different ones for a good measure plus flashing to original and then back to unlocked ones again. Also I have lost the SNRm - it has gone back from 8,2dB down to 6 and below even at night. It was creeping down ever so sligtly taking max attainable with it (down to 50000 ish at 5,3).

Then following morning modem resynced on the fly at 4am and I was put on heavier interleave. Ping went from 16ms up to 27ms, sync got limited to 37,7 on downstream. So clearly my messing around got me in trouble with dlm... I havent got full stats stats from that moment just a snippet of errors just after re-syncing. See below:

Line rate (kbit/s) 37735 10000 0 0
CRC errors 719 0 0 0
FEC errors 7 0 0 0
HEC errors 42 0 0 0

I did not stop there though. I decided that something else must be wrong here with the wiring. When the engineer installed everything he also moved master from where it used to be to the lounge. I had two extensions also previously so he just rewired them bacwards from the new master going trough the same four pair twisted cable I believe. So crimps at the old master plus crimps at the extension one and new master instead extension two. then backwards trough the same cable to extension one and extension two at the old master. All connected to mk2.

Firstly I proceeded to disconnecting all of the extensions. It did not make much difference to be honest apart from fewer errors on line at the time of testing. Nothing conclusive. So I thought last thing I can do is disconnect the extension wires from mk2 faceplate. Whilst doing that I swopped the incoming around again for a good measure. In response to b4dger and Zarjaz this did not make any difference. At least I dont believe that it did. I believe I had issue with the extensions wired to the mk2 going back trough the same cable. Initially after disconnecting the wires I got 70 on downstream At this point I was screwed anyway with the latency but my speed went bac up to 39999. Errors looked preety good to. Stats below from around eleven twelve last night :

# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Max: Upstream rate = 20887 Kbps, Downstream rate = 70528 Kbps
Path: 0, Upstream rate = 10000 Kbps, Downstream rate = 39999 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): 9.6 12.2
Attn(dB): 0.0 0.0
Pwr(dBm): 13.9 7.4
VDSL2 framing
Path 0
B: 26 47
M: 1 1
T: 64 64
R: 16 16
S: 0.0215 0.1521
L: 16025 3366
D: 2019 211
I: 43 64
N: 43 64
Counters
Path 0
OHF: 4095062 870442
OHFErr: 1 0
RS: 1572503390 3768198
RSCorr: 3115 0
RSUnCorr: 26 0

Path 0
HEC: 11 0
OCD: 0 0
LCD: 0 0
Total Cells: 651615839 0
Data Cells: 5166713 0
Drop Cells: 0
Bit Errors: 0 0

ES: 1 0
SES: 0 0
UAS: 17 17
AS: 8474

Path 0
INP: 8.00 4.00
PER: 2.06 9.73
delay: 11.00 8.00
OR: 93.16 59.16

Bitswap: 197 7

Total time = 2 hours 21 min 32 sec
FEC: 3115 0
CRC: 1 0
ES: 1 0
SES: 0 0
UAS: 17 17
LOS: 0 0
LOF: 0 0
Latest 15 minutes time = 6 min 32 sec
FEC: 18 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 2 hours 21 min 32 sec
FEC: 3115 0
CRC: 1 0
ES: 1 0
SES: 0 0
UAS: 17 17
LOS: 0 0
LOF: 0 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
Since Link time = 2 hours 21 min 13 sec
FEC: 3115 0
CRC: 1 0
ES: 1 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0


Furthermore... I did all this last night including suddenly pullling the face plate of the master thus losing connection (LOS). This morning I have found that I got another resync on the fly. It was rather interesting result tho as ping went down and SNRm gone up to 13dB ish.
I got burst of errors but this happened during the resync so I am not too worried about. Interesting is error rates since the link up
Below see stats taken just now :


# xdslcmd info --stats
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 2
Max: Upstream rate = 19385 Kbps, Downstream rate = 70328 Kbps
Path: 0, Upstream rate = 9999 Kbps, Downstream rate = 39996 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): 13.2 12.8
Attn(dB): 0.0 0.0
Pwr(dBm): 13.9 7.4
VDSL2 framing
Path 0
B: 57 236
M: 1 1
T: 64 23
R: 16 16
S: 0.0461 0.7543
L: 12835 2694
D: 701 1
I: 74 127
N: 74 254
Counters
Path 0
OHF: 17794515 691039
OHFErr: 4 0
RS: 3416546547 3559522
RSCorr: 3873 0
RSUnCorr: 12 0

Path 0
HEC: 4 0
OCD: 0 0
LCD: 0 0
Total Cells: 3041431422 0
Data Cells: 10680089 0
Drop Cells: 0
Bit Errors: 0 0

ES: 8 0
SES: 6 0
UAS: 35 35
AS: 39548

Path 0
INP: 3.00 0.00
PER: 2.21 8.67
delay: 8.00 0.00
OR: 86.72 59.02

Bitswap: 78 7

Total time = 21 hours 14 min 36 sec
FEC: 13169 0
CRC: 2599 0
ES: 8 0
SES: 6 0
UAS: 35 35
LOS: 5 0
LOF: 5 0
Latest 15 minutes time = 14 min 36 sec
FEC: 449 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 2 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
Latest 1 day time = 21 hours 14 min 36 sec
FEC: 13169 0
CRC: 2599 0
ES: 8 0
SES: 6 0
UAS: 35 35
LOS: 5 0
LOF: 5 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
Since Link time = 10 hours 59 min 7 sec
FEC: 3873 0
CRC: 4 0
ES: 1 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0


I dont know what to say other than it seems vdsl is very sensitive indeed to any dodgy wiring and that I am lucky to go from 40 on downstream max attainable to 70 after some messing with my home wiring. With current error rates I am hoping that dlm will reletn even more and that my pings will be even lower. I am happy with the 40 meg service as this gives me now plenty of overhead space for any crosstalk and other surprises so I am not even thinking about going on to the faster package. Want my pinge back to below 10ms

Cheers Kamil

Edited by deleted (Sun 31-Aug-14 21:12:29)

this firmware has the same dsl code as the previous (blob) it is believed the only thing changed is the VOIP bug that revk of aaisp reported been fixed.

Edited by Chrysalis (Sun 31-Aug-14 22:11:20)

I guess is purely coincidence then. None the less this is what started after updating. But downgrading did not make any difference either. Only removing extensions did.

I don't suppose you have any Hlog graphs from when the extensions were connected & after you disconnected them do you?


What you describe could have been causing a bridged tap effect.


The Hlog graphs would show a pronounced valley with a bridged tap (impacting on attainable rates & sometimes actual sync speeds) & a much smoother curve without it.

I have them thanks to you and other guys who made this possible

Please see links below as I can not insert pictures here. (Is it even possible?)

Firstly with extensions still attached :

http://i1133.photobucket.com/albums/m582/kamilrott/h...
http://i1133.photobucket.com/albums/m582/kamilrott/h...

Second one after disconnecting everything:

http://i1133.photobucket.com/albums/m582/kamilrott/h...

Regards, Kamil

Edited by deleted (Sun 31-Aug-14 22:55:48)

The first 2 graphs do show bridged tap symptoms (2 of them).

The 3rd one (after disconnecting the extensions) is how a healthy Hlog should look.

Who needs an expensive JDSU ???




I have a number of extensions wired from the downstairs faceplate to upstairs & then back downstairs again to another room.

They are connected in 'daisy chain' manner & thus I see no signs of bridged taps at all in my Hlog graphs.



My drop wire was replaced to come in directly to the downstairs master socket a couple of years ago in an attempt to fix an intermittent, but quite frequent disconnection fault.

It originally came into the upstairs master socket.

The original installing BTOR engineer used my shielded 2 pair extension cable from upstairs to make the master socket downstairs.

He used the other pair in the extension cable to backwire to what was originally the master socket upstairs to make it an extension.

From there, the other extensions were wired, again in 'daisy chain' manner.

That wiring setup was fine & again, there were no bridged tap extensions.


I believe backwiring is somewhat frowned upon, but using decent cable & correctly wired it doesn't actually seem to do any harm.


The intermittent fault was eventually traced to a dodgy connection where the undergound cable connected to the pole top mounted DP.





If you do reconnect the phone extensions, try to do them in a daisy chain manner & re-check your Hlog graph on completion.

Note that Hlog & QLN graphs are only updated when a connection resyncs, during the training phase.

So you may need to force a resync to ensure you are viewing the updated graphs.

Thanks for confirmation on Hlog

The original installing BTOR engineer used my shielded 2 pair extension cable from upstairs to make the master socket downstairs.

Mine was done in similar manner except all on one floor. old extension converted to new master trough four pair twisted cable that was already in place.

Then the installer back wired trough the same cable two extensions in as you say a `daisy chain` manner.

I dont think its wise to use this cable for wiring extensions and I can not run new cable trough the cavities as this is rented property.

I only use one telephone so quite happy to leave it as it is and use it at the master socket.


Ps. I am reading trough your thread (FTTC - Distance from the Cabinet - Realistic speed estimate) as there is some intereting stuff in there. I am currently on page no.27 but now you have told me the conclusion lol. I will still carry on as I want to see what has bt and plusnet done in before the final solution.

Regards

In reply to a post by Kamil:

Ps. I am reading trough your thread (FTTC - Distance from the Cabinet - Realistic speed estimate) as there is some intereting stuff in there. I am currently on page no.27 but now you have told me the conclusion lol. I will still carry on as I want to see what has bt and plusnet done in before the final solution.

Haha!

That's the SHORT version of my epic tale!!!!!


I do have to acknowledge my gratitude to Plusnet for their perseverence over the 11 months it took to finally fix the intermittent issue.

I'm not convinced that all ISPs would have done that.

I do have to say though, that without detailed stats & particularly the graphs, I might not have fared quite so well.

If anyone ever wondered, that's why I wrote the monitoring/graphing programs (with much assistance from others who still frequent this & the Kitz forums, including the maestro himself, Asbokid)