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New Fibre Install - Great download, Poor upload speeds. - Please advise

Community Veteran
Posts: 1,412
Thanks: 4
Registered: ‎29-01-2009

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

I just posted this over on your TBB thread. Hope it helps...
Quote
Looking at your posts on the PN forum, the main issue you seem to be facing is that the upstream bitloading is pretty bad - especially in the U2 band starting around tone 1980. This is resulting in a low sync speed.
It doesn't look like DLM has artificially lowered the upstream speed, as this low sync speed is achieved with the standard 6dB noise margin. "Banding" by DLM, or artificially setting a low sync speed, will result in an SNRM level notably higher than 6dB.
In fact, from the "--stats" output that is visible in the "pastebin" link, we can see that DLM hasn't intervened at all yet. The error rate (600 ES's in 10 hours) isn't enough to trigger DLM - at least not on a PN line.
You appear, at first glance, to be getting decent downstream speeds. Ordinarily, that would suggest that you are either suffering from noise and interference that is particular to the upstream frequencies, or you are transmitting at too low a power level - though there isn't necessarily anything you can do about either.
However, the bitloading graph shows your downstream loading has been done very differently from the norm too (see link later for a comparison example). Ordinarily, I'd expect a lot more of the D3 band to be used - instead, you seem to have a small "blip" of D3, and a lot of extra bits in D2 and D1.
Overall, it looks strange, suspicious even, and suggests your line isn't working as normal at all ... so perhaps your latest discovery of a tree rubbing the distribution cable is indeed the cause of the issues.
It might be useful to post a few more things from the HG612:
- The Hlog graph, which might give an idea of the state of the copper
- The QLN graph, which indicates how noisy your line is
- The SNR graph
- The data from the "--pbParams" command
All of these are things you can get from tabs on DSLstats; the latter two are within the "telnet data" tab.
It is probably easier to post images over on PN's forum, with a post here to say you've done it.
Other notes:
- Where you see reduced bit loading below tone 180 ... is normal. The FTTC cabinet is configured to reduce power on lower tones, so it doesn't interfere with ADSL signals from the exchange. The setting varies for each cabinet, so for some you see this notch at different tones.
- Your attenuation is 18.8dB, which is consistent with the speed estimates that BT provide. 80Mbps is certainly feasible downstream, just about, but it could easily drop somewhat as it gets affected by crosstalk - which will happen with increasing subscriber numbers.
Other posters are getting hung up on how long your line is, but they are forgetting that the gauge (thickness) of the copper is important, as well as the length.
An old line of mine had a 16.7dB attenuation, and was about 370m from the cabinet. That would suggest your line is behaving like a line that is only 410m long. However, it is entirely possible that your line uses thicker copper than normal - perhaps 0.6mm instead of 0.5mm.
That line started with an attainable speed of about 90Mbps, but that dropped as crosstalk took effect over 3 years, dropping eventually to 78Mbps.
The upstream attainable was well over 20Mbps throughout. Ordinarily, you ought to be in that region.
For comparison, here is what the graphs look like for that line:
http://postimg.org/image/vyrngmb11/
- I've had an even older line, that was 650m of copper. This was back in the days when only the 40/10 package existed, but it achieved a 10Mbps upstream easily, and reported an attainable of 16Mbps.
- The agent who told you "favouring download over upload" is talking nonsense. The distribution of upstream frequencies vs downstream ones is fixed nationwide, and everyone gets favoured the same.

Plusnet Customer
Using FTTC since 2011. Currently on 80/20 Unlimited Fibre Extra.
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

Thanks Terra, I thought it was nonsense.
Cracking post there WWWombat, thank you very much. I'll get those stats you've requested up asap, I'd forgotten about my ThinkBroadband post!  Roll_eyes
Community Veteran
Posts: 19,106
Thanks: 447
Fixes: 21
Registered: ‎31-08-2007

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

OK, this is totally off the wall - considering who did the install  ;), what would happen if the ADSL was not disconnected at the exchange. Whilst there are filters in the Cab, no filter has perfect attenuation so the Interference from the ADSL could clobber some of the tones particularly the US of which you appear to have none in the U0 band (going by the bit loading plot on reply #15).
This is the 2nd thread I've read where there's an unexplained loss of speed but particularly on the US where the bit loading was not what was expected.
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

I welcome all theories Another one  Smiley
I wish a tech would reply on here with their opinion, at the moment I feel like I'm lost within the Line Faults department, being passed from tech to tech with no solution in sight. This issue needs ONE Plusnet tech support person to manage it and see it to the end.
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

Quote from: WWWombat

It might be useful to post a few more things from the HG612:
- The Hlog graph, which might give an idea of the state of the copper
- The QLN graph, which indicates how noisy your line is
- The SNR graph
- The data from the "--pbParams" command

Here we go!  Wink
I've also added another bitloading. Are the SNRperband of any use to you? I can upload those if required.
Quote
xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 0
Last initialization procedure status: 0
Max: Upstream rate = 8883 Kbps, Downstream rate = 71284 Kbps
Bearer: 0, Upstream rate = 8879 Kbps, Downstream rate = 72375 Kbps
Discovery Phase (Initial) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3959)
Medley Phase (Final) Band Plan
US: (7,32) (871,1205) (1972,2550)
DS: (33,859) (1216,1961) (2793,3959)
  VDSL Port Details   Upstream   Downstream
Attainable Net Data Rate:     8883 kbps     71284 kbps
Actual Aggregate Tx Power:       5.9 dBm     12.9 dBm
====================================================================================
  VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
  Line Attenuation(dB): 5.6 27.2 44.4 N/A N/A 13.8 35.1 61.1
Signal Attenuation(dB): 5.6 26.6 42.1 N/A N/A 15.4 34.8 61.3
        SNR Margin(dB): 6.2 6.3 6.3 N/A N/A 5.9 5.9 5.9
        TX Power(dBm): 0.4 -15.6 4.5 N/A N/A 9.8 7.7 6.1

Community Veteran
Posts: 19,106
Thanks: 447
Fixes: 21
Registered: ‎31-08-2007

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

I think you can chuck my last theory out of the window for your connection. The U0 band on this last bit loading graph looks OK.
Community Veteran
Posts: 6,340
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Registered: ‎08-01-2008

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

The posted QLN and HLOG graphs only show up to ~tone 440, can you get graphs covering all tones, I think there might be a lot more to see on the higher tones?
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
Community Veteran
Posts: 38,460
Thanks: 1,032
Fixes: 62
Registered: ‎15-06-2007

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

Comparing it to my bit loading - similar upstream speed but a lot longer line - the problem appears to be in the 900 - 1200 band but why that should be I have no idea specially since the higher bands are much better than mine
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

My apologies, I hadn't noticed the higher tones.
I've attached two updated ones now, Thanks.
Community Veteran
Posts: 5,400
Thanks: 589
Fixes: 25
Registered: ‎10-06-2010

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

Perhaps the low upload speed is due to the amount of Upstream Power Back Off (UPBO). That means the transmit power of your upstream has been reduced so that when it arrives at the cabinet, it's the same strength as the upstream from someone with a much longer line. If this wasn't done, then your upstream signals would be much stronger, when received at the cabinet, than those from a longer line, and then your upstream could interfere with the upstream from longer lines.
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

Hi ejs,
I've had a slow upstream since day one of the install, I was the second user to be jumped onto the new cab at that point, the other user is/was a neighbour 600 metres in the opposite direction, he gets the 20 upload and 70+ downsync!
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

G.INP enabled after a forced resync by the cab 24 hours ago?
Looks like interleaving has now been applied too.
Quote
xdslcmd info --pbParams
xdslcmd: ADSL driver and PHY status
Status: Showtime
Retrain Reason: 1
Last initialization procedure status: 0
Max: Upstream rate = 8752 Kbps, Downstream rate = 74844 Kbps
Bearer: 0, Upstream rate = 8752 Kbps, Downstream rate = 77490 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Discovery Phase (Initial) Band Plan
US: (7,32) (871,1205) (1972,2782)
DS: (33,859) (1216,1961) (2793,3959)
Medley Phase (Final) Band Plan
US: (7,32) (871,1205) (1972,2550)
DS: (33,859) (1216,1961) (2793,3959)
 VDSL Port Details  Upstream  Downstream
Attainable Net Data Rate:     8752 kbps    74844 kbps
Actual Aggregate Tx Power:       6.0 dBm     13.1 dBm
====================================================================================
 VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
 Line Attenuation(dB): 5.5 27.0 44.2 N/A N/A 13.7 34.9 60.9
Signal Attenuation(dB): 5.5 26.4 41.9 N/A N/A 15.3 34.6 61.0
       SNR Margin(dB): 5.8 6.1 6.2 N/A N/A 5.8 5.8 5.8
        TX Power(dBm): 0.2 -16.2 4.6 N/A N/A 10.2 8.0 5.9
#
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

Massive rain and wind storm just hit.. this has shown up on the stats  Huh Does this indicate a line issue?
Community Veteran
Posts: 5,400
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Registered: ‎10-06-2010

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

I think that kind of dip on the HLog graph shows a "bridged tap", and the tone at the bottom of the dip can be used to work out the length of the bridged tap, which I think works out as very short, maybe about 5m.
A bridged tap is basically some piece of wiring connected to your line that shouldn't be. Internal extension wiring could act as a bridged tap if the DSL signal goes along it, if the extension wiring isn't connected via a filter.
Is your phone extension wiring connected to the removable lower front plate of the master socket?
Thetwohoughs
Grafter
Posts: 55
Registered: ‎05-12-2015

Re: New Fibre Install - Great download, Poor upload speeds. - Please advise

Thanks for the reply!
There is an extension that's connected via the Front Plate on the master socket, this runs through the attic then back down to supply the house phone. I've disconnected it before with no noticeable change to the connection stats.
The Openreach Modem is fed via the Filter on the MK3 Faceplate. It's also worth noting that the Engineer had his tester plugged into the test port of the NTE5A and could only get a max upsync of around 8000 - 9000 with the cab, does this rule out internal wiring?