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Upstream speed high on long line

ggunner
Hooked
Posts: 6
Registered: 17-09-2016

Upstream speed high on long line

Hello there,

I live around 4.km from the nearest cabinet so have fairly poor broadband speeds. However, recently my upstream speed which was always around the 440kbps mark has increased to around 930kbps. This is creating all sorts of bit errors etc. The thing I find most strange is that my attainable upstream rate is sometimes less than my actual rate, there is no margin between like my downstream. Because of this I feel its affecting my attainable downstream with all these errors.

Hopefully someone can shed some light on this issue.

SNR Margin (dB) 12.0 5.9
Attenuation (dB) 54.0 32.5
Output Power (dBm) 0.0 12.6
Attainable Rate (Kbps) 2816 928
 
Rate (Kbps) 2563 928
10 REPLIES
Community Veteran
Posts: 5,109
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: Upstream speed high on long line

I don't think it's likely that your downstream is being affected by your high upstream speed.

There's obviously some problem with the downstream because the SNR Margin at 12 is higher than the usual. But it's more likely to be some general problem with your line, internal wiring, filter(s) or modem/router.

Community Veteran
Posts: 38,460
Thanks: 1,027
Fixes: 62
Registered: 15-06-2007

Re: Upstream speed high on long line

It is likely that either you have been moved to 21CN or Plusnet have uncapped the upload

Regarding the attainable downstream being higher than actual this is because your default noise margin has increased from 6dB to 12dB

Errors on upstream won't directly affect the downstream

ggunner
Hooked
Posts: 6
Registered: 17-09-2016

Re: Upstream speed high on long line

Hi ejs, I've recently overhauled the internal wiring and removed all secondary cabling, fitted faceplate filter and replaced my router with a billion 7800dlx. BT cable is well away from power sources.

ggunner
Hooked
Posts: 6
Registered: 17-09-2016

Re: Upstream speed high on long line

Oldjim, will the errors on the upstream add to the errors being picked up by the DLM?

ggunner
Hooked
Posts: 6
Registered: 17-09-2016

Re: Upstream speed high on long line

Perhaps more diagnostics from my router may help, the line has been up for 4 hours.

  Downstream Upstream
Line Coding (Trellis) On On
SNR Margin (dB) 12.1 5.8
Attenuation (dB) 54.0 32.5
Output Power (dBm) 0.0 12.6
Attainable Rate (Kbps) 2836 932
 
Rate (Kbps) 2563 928
 
K (number of bytes in DMT frame) 0 0
R (number of check bytes in RS code word) 0 0
S (RS code word size in DMT frame) 0 0
D (interleaver depth) 16 4
Delay (msec) 8 5
INP (DMT symbol) 1.00 0.00
 
Super Frames 888481 802246
Super Frame Errors 65 3
RS Words 28875590 3015823
RS Correctable Errors 165220 23
RS Uncorrectable Errors 113 0
 
HEC Errors 35 0
OCD Errors 0 0
LCD Errors 0 0
Total Cells 87171709 31517032
Data Cells 11790688 994479
Bit Errors 0 142
 
Total ES 65 3
Total SES 0 0
Total UAS 45 45
Community Veteran
Posts: 5,109
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: Upstream speed high on long line

Those stats show there are hardly any errors, especially on the upstream.

I think K, R, S are more applicable to ADSL1, and this is evidently ADSL2/2+, which may explain why those all show as zero.

What exchange are you on?

ggunner
Hooked
Posts: 6
Registered: 17-09-2016

Re: Upstream speed high on long line

Well thats what I thought yesterday but this morning there were thousands of HEC and bit errors etc after 24hrs. Exchange is Wick NSWIC.

Community Veteran
Posts: 5,109
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: Upstream speed high on long line

I think that exchange has been 21CN for a fairly long time, perhaps Plusnet uncapped your upstream while moving you to their "new network", if they moved you recently. Or it's recently been uncapped for some other reason.

ggunner
Hooked
Posts: 6
Registered: 17-09-2016

Re: Upstream speed high on long line

Slight update, had plusnet cap my upload to 440kbps in a bid to reduce errors which seems to have worked, problem is my interleaver profile has now changed and although my attainable downstream is 3500kbps I'm only acheiving 2200kbps. Perhaps some gurus could help diagnose?

Mode ADSL_2
Traffic Type ATM
Status Up
Link Power State L0
 
  Downstream Upstream
Line Coding (Trellis) On On
SNR Margin (dB) 7.3 20.5
Attenuation (dB) 55.0 32.5
Output Power (dBm) 0.0 12.6
Attainable Rate (Kbps) 3516 940
 
Rate (Kbps) 2268 444
 
K (number of bytes in DMT frame) 0 0
R (number of check bytes in RS code word) 0 0
S (RS code word size in DMT frame) 0 0
D (interleaver depth) 416 1
Delay (msec) 7 0
INP (DMT symbol) 4.00 0.00
 
Super Frames 11753234 10783166
Super Frame Errors 1747 312
RS Words 928280256 3864954
RS Correctable Errors 899202 0
RS Uncorrectable Errors 0 0
 
HEC Errors 707 346
OCD Errors 0 0
LCD Errors 0 0
Total Cells 85627619 16758828
Data Cells 7044769 481467
Bit Errors 0 0
 
Total ES 1205 194
Total SES 10 6
Total UAS 134 124
Community Veteran
Posts: 5,109
Thanks: 465
Fixes: 17
Registered: 10-06-2010

Re: Upstream speed high on long line

They haven't only capped the upstream (probably fairly pointlessly), it looks like they've also set a banded profile with a higher than usual INP level of 4, which has resulted in the very high interleaving depth (for ADSL) of 416.

You need someone from Plusnet to confirm, but it certainly looks like they've set INP (interleaving) to high, and I think that can only be done in conjunction with banded speed profiles.