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Banded?

Townman
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Re: Banded?

@Gandalf

Is the upstream still capped here?

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Anoush
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Re: Banded?

Looks like interleaving may be applied. If the upstream was capped, it’d be around 448kbps. Interleaving as a form of error correction can put an upstream sync to around 888kbps. 

This is my personal Community Forum account to help out around these parts while I'm at home. If I'm posting from the 1st March 2020, this means I'm off-duty with no access to internal systems.
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redsox9
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Re: Banded?

Thanks for replying from home Anoush. If interleaving is applied will turning it off increase my upload speed and decrease my download speed?  I  am not a gamer.  If I had to choose between a higher DS and a higher US I would prefer the former.  But can't I have both?

Townman
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Re: Banded?

US and DS streams are separate.

I asked if the US is capped as it’s SNRM is 12dB suggesting that there might be some room for improvement. One would hope that a clean line as short as yours might have a “better” US profile.

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redsox9
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Re: Banded?


I could certainly do with a better upload speed profile and hope Plusnet will fix it without me raising another fault.

Gandalf
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Re: Banded?

I've put through a DLM change to remove interleaving which has dropped your connection to apply the change but it's been over 5 minutes so far and your connection's not come back up. ‌Sad

Could you reboot your router and let me know how it goes?

[edit]

I see your connection's back now. 

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 Anoush Mortazavi
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redsox9
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Re: Banded?

Here are my latest stats.

DS is even better but US is the same.

 

System Up Time 00:01:28

Port      Status  TxPkts  RxPkts  Collisions          Tx B/s   Rx B/s   Up Time

WAN    PPPoA  581       561       0            3686     11464  00:00:36

LAN      10M/100M       799       1276     0            5905     2596     00:01:24

 

ADSL Link          Downstream    Upstream

Connection Speed       18701 kbps       883 kbps

Line Attenuation          20 db   5 db

Noise Margin  6 db      13 db

 

BT

Performance Test Results Report Basic Performance Test - Time Stamp Latency Download Upload Monday 24 August 2020 | 10:15:27 46 Ms 12.81 Mbps 0.76 Mbps Advanced Performance Test - Download Test Download speed achieved during the test was 12.81 Mbps For your connection, the acceptable range of speeds is 4-21 Mbps Your DSL Connection Rate: 0 Mbps(DOWN-STREAM),0 Mbps(UP-STREAM) For your connection, the maximum achievable download speed is 21 Mbps IP Profile for your line is 16.5 Mbps Upload Test Upload speed achieved during the test was 0.76 Mbps For your connection, the maximum achievable upload speed is 0.83 Mbps IP Profile for your line is 0.83 Mbps Summary Advanced Performance Test - Result Message We were unable to identify any performance problem with your service at this time.It is possible that any problems you have experienced may have been caused by traffic congestion or by a server responding slowly. Please visit the Speed Test Guidance if you are unable to understand the test results.

Townman
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Re: Banded?

@Gandalf @Anoush 

Thank you for the TLC here, however there still seems to be something quite odd here.  Back at post #16 before the line was "fixed" the US SNRM was 9dB delivering 1.028mbps - now it is 13dB* delivering .883mbps

Is this a problem with the BTw profile?  Is this a factor of the "speed" vs "standard" discussion had elsewhere?

 

Also 13dB hints at the presence of noise at the time of the sync-up process ... which might tie-in with the delay in syncing you observed.  Though markedly better, this line is still a bit shy of its on-paper potential.

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Gandalf
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Re: Banded?

Let me see what I can do although I'd need to wait until tomorrow as only one DLM change can be processed per 24 hours. I'll post back before the close of play tomorrow.

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redsox9
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Re: Banded?

Was the DLM change made?  I rebooted my router and here are the latest stats. DS has dropped from 18701 kbps to 16871 but US is up from 883kbps to 1098.

Did DS drop because it was my second reboot in 26 hours?

 

Router:

System Up Time 00:01:34

Port      Status  TxPkts  RxPkts  Collisions          Tx B/s   Rx B/s   Up Time

WAN    PPPoA  333       321       0            1780     5896     00:00:39

LAN      10M/100M       579       1045     0            3579     1707     00:01:30

 

ADSL Link          Downstream    Upstream

Connection Speed       16871 kbps       1098 kbps

Line Attenuation          20 db   5 db

Noise Margin  6 db      7 db

 

BT :

Performance Test Results Report Basic Performance Test - Time Stamp Latency Download Upload Wednesday 26 August 2020 | 7:44:55 37 Ms 14.35 Mbps 0.95 Mbps Advanced Performance Test - Download Test Download speed achieved during the test was 14.35 Mbps For your connection, the acceptable range of speeds is 4-21 Mbps Your DSL Connection Rate: 0 Mbps(DOWN-STREAM),0 Mbps(UP-STREAM) For your connection, the maximum achievable download speed is 21 Mbps IP Profile for your line is 14.88 Mbps Upload Test Upload speed achieved during the test was 0.95 Mbps For your connection, the maximum achievable upload speed is 0.83 Mbps IP Profile for your line is 0.83 Mbps Summary Advanced Performance Test - Result Message We were unable to identify any performance problem with your service at this time.It is possible that any problems you have experienced may have been caused by traffic congestion or by a server responding slowly. Please visit the Speed Test Guidance if you are unable to understand the test results.

 

Gandalf
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Re: Banded?

Sorry for the delay, I got caught up in something yesterday. I can confirm that interleaving's been switched off:

Profile Info: WBC 160K - 24M Medium delay (INP 1) 6dB Downstream, UC Low delay (INP 0) 6dB Upstream (ADSL2+)

INP 0 suggests that interleaving is switched off on the upstream.

INP 1 means that interleaving's enabled in a low/automatic state on the downstream.

Testing your line is showing what you're seeing that your upload speed's increased and your download's gone down slightly, which would likely be on the back of the increase to the upstream as ADSL is asymmetric, so one can affect the other.

xDSL Status Check
Circuit ID: [redacted] Service ID: [redacted]
Telephone NO.: NA Test Executed On: 26-08-2020 07:53:18
xDSL Status Test Summary
Sync Status: Circuit In Sync
General Information
NTE Status:   NTE Power Status: PowerOn Bypass Status:  
 
  Upstream DSL Link Information Downstream DSL Link Information
Loop Loss: 10.6 20.5
SNR Margin: 6.5 6.6
Errored Seconds: 0 41
HEC Errors: 0  
Cell Count: 236910 1109078
Speed: 1098 16871
 
Maximum Stable Rate (KBPS): 2272 Fault Threshold Rate (KBPS): 2272
Mean Time Between Retrains (Seconds): 86400 Mean Time Between Errors Upstream (Seconds): 86400
Indicative Line Quality: A Mean Time Between Errors Downstream (Seconds): 78

If you're preferring a higher download speed than upload I could either permanently switch interleaving on, or manually cap the upload speed to around 440kbps.

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 Anoush Mortazavi
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Townman
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Re: Banded?

Anoush,

As I understand things, asymmetric here simply means that they are not the same. US and DS tone bins are not shared or exchanged under standard options.

The current performance is way better than what has been see here before, but not as good as that which might be expected on such a short line, which is reporting Amber. The DS error rate MTBE looks rather poor. It might be worth just watching To see where this goes and then review accordingly.

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Gandalf
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Re: Banded?

I've checked this with a faults colleague (One of the guys who coached me on faults back in the day) and it's definitely normal to see a download speed drop on ADSL after basically uncapping an upload speed.

I'm happy to leave things as they are and see where they go.

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 Anoush Mortazavi
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RealAleMadrid
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Re: Banded?

I agree with @Townman , there should be no difference in the downstream speed when upstream interleaving is disabled. The frequency bins do not change. It looks like there is now some interleaving on the downstream (medium delay INP 1) which could explain the lower downstream speed.

@Gandalf  I suspect you and/or your colleague could be thinking of ADSL2+ Annex M which gave a higher upstream speed by trading off the downstream speed, which did change the bin allocation to achieve this.🤔

Townman
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Re: Banded?

@RealAleMadrid 

Thank you for affirming my thoughts on this.  I was out and about when I made my last reply and it was not practical to check resources on this subject.  Annex M does indeed change tone allocations to deliver up to 3.3mbps upstream, but Annex M is (IIRC) only offered on business grade services.  I believe that the service offered by Plusnet to residential users is G.992.5 Annex A

See...

  1. https://en.wikipedia.org/wiki/G.992.5
  2. https://en.wikipedia.org/wiki/G.992.3
  3. https://en.wikipedia.org/wiki/ITU_G.992.5_Annex_M
  4. http://www.equicom.hu/wp-content/uploads/EXFO_Reference-Guide-Local-Loop-DSL-v1_en.pdf is an interesting read (especially from page 49)
  5. https://community.plus.net/t5/ADSL-Broadband/ADSL2-is-live/m-p/651801

The last (internal) resource is an interesting read...

For upstream speed things are a little different. We have a choice of fixing the upload speed to 448kbps or leaving it uncapped (which has a maximum sync rate around 1Mbps). With DSL technologies there is always a trade off between speed and stability, setting the upstream speed to 448kbps means that the line (in one direction at least) doesn't run at the limits of what it's capable of so can offer a slightly more stable experience. We have also noticed that lines set to 448kbps can sometimes run at a slightly faster downstream rate, again we think this is down to the line not running at the limits in both directions so less errors will be seen on the line and thus the line remains more stable.


Overlooking the whole speed vs stability piece is BT's DLM (Dynamic Line Management) system. DLM has been designed to analyse the stability of every line on a constant basis and, if necessary, make changes to line characteristics each day. DLM will look at how many disconnections a line has had (it should be able to tell the difference between a loss of sync and someone switching the router off), look at the amount of errors on line, see what changes have previously been made, see how much downtime the line has had and make decisions based on those as to what to do.

This points to errors on the line causing a slower DS in the presence of a higher US, rather than a technology standards trade off.  As I noted, the DS MBTE is very low.  The best speed seen after the engineer's visit is still below that expected on such a short line: 20db attenuation suggests 1.4km, whilst the OP reports circa 700m.  How do these figures compare to  BTw's resistive and capacitive line length estimates?

Is the line free of bridge taps?

Are the resistive, capacitive and longitudinal balances all looking good?  I note from page 61 of (4) above ...

Note that loops that have improper longitudinal balance act as an efficient crosstalk receiver or transmitter. This is why a single, poorly balanced loop can bring down an entire bundle.

Thus the issue being experienced might be out-with the OP's circuit and therefore out-with PlusNet's scope to influence a resolution.

 

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