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Fibre - Speed Issues - Lack of Understanding by PN

daveg6hni
Grafter
Posts: 183
Thanks: 5
Registered: 07-01-2009

Fibre - Speed Issues - Lack of Understanding by PN

On 1st April 17 my download speed dropped from 35.8Mbps down to less than 28Mbps and my BT sync dropped from greater than 39Mbps down to 28.8Mbps.

I've had two visits from OpenReach engineers who did nothing more than test the line and declare it OK, the second one said that before they can do any actual fault finding PN need to escalate the issue.

Yet neither engineer or PN could explain why my Sync & Download speed remain slow.

My modem is a standard BT Huawei HG612 3B which is plugged directly into the master NTE5 wall socket.

I have no internal twisted pair wiring and I have left my DECT base unplugged, but that made no improvement.

In the end I bought a new modem (TP-Link TD-W9970) which tells be that I'm now only syncing at exactly 34999Kbps although my line could sync at up to 44-45500Kbps and although the max sync does vary slightly my actual sync is rock solid 34999Kbps ?

I suspect that PN have placed a cap on my sync speed to try and mask the fault ?

Also PN seem incapable of understanding that there is a fault, each time someone replies to my ticket they look at my line in isolation and say it is working within acceptable limits !

They ignore, or avoid, or cannot answer why it suddenly dropped by some 20% and do not seem to be bothered in resolving it. I have even asked to speak to a supervisor just to get them to acknowledge there is still a fault.

Am I being unreasonable ?

Should I accept that a 20% reduction in my download speed is acceptable ?

I attach a graph from my SamKnows White box which shows my download speed since 1st May 2015, you can see that my line has become increasingly unstable up until 1st April and then just dropped by 20%

From my SamKnows stats My Latency is around 45ms, Packet Loss is usually 0, but there have been a noticeable increase in spikes in the last six months, DNS response time is around 10ms. 

To me that says there is something wrong, PN see no issues though Huh

How can I get PN to treat this issue seriously ? or better still fix it ?

All suggestions gratefully received.

Here is a link to my Think Broadband live quality monitor https://www.thinkbroadband.com/broadband/monitoring/quality/share/354b6b4aaa871f3a524bb8f62fec5ece37...

50 REPLIES
Plusnet Help Team
Plusnet Help Team
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Registered: 21-04-2017

Re: Fibre - Speed Issues - Lack of Understanding by PN

Sorry to hear you're having problems.

 

Testing your broadband service is showing your downstream speed in sync at 35 Mb/s...

 

Sync Status In Sync
Downstream Speed 35.0 Mbps
Upstream Speed 6.9 Mbps

 

That's likely caused by the banding...

Profile Name 0.128M-35M Downstream, Retransmission Low - 0.128M-10M Upstream, Error Protection Off

This isn't a cap placed by Plusnet, it's something that the DLM in the exchange does automatically.

 

Testing your line is identifying no issues...

Voice Line Test Result Pass

 

Your connection is also stable except for the odd drop here and there...

 

Unfortunately, as the line tests are passing, connection stable and your speed remains within your estimated speed range of between 32.4 Mb/s and 42 Mb/s, it's unlikely an engineer will investigate further I'm afraid.

 

Apologies for any frustration caused.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
daveg6hni
Grafter
Posts: 183
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Registered: 07-01-2009

Re: Fibre - Speed Issues - Lack of Understanding by PN

You see, yet again you have not offered or avoided any explanation for the 20% drop in performance.

 

Just saying it is within acceptable limits, is not acceptable to me when I have been getting 20% more right up until 1st April.

 

Please just answer the question why has it dropped by 20% overnight and what are you going to do to restore it ?

Community Gaffer
Community Gaffer
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Re: Fibre - Speed Issues - Lack of Understanding by PN

There can be multiple reasons for speed to drop, unfortunately we cannot report a fault where a fibre line is within the estimates as this will be rejected. You may find that the speed increases again, or it may not.

If this post resolved your issue please click the 'This fixed my problem' button
 Chris Parr
 Plusnet Staff
Phill
Hooked
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Re: Fibre - Speed Issues - Lack of Understanding by PN

Do you have some router stats? Does it show the Interleaving level on the downstream? DLM is a nightmare for sure. Has the line attenuation changed at all? or the SNR?

daveg6hni
Grafter
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Registered: 07-01-2009

Re: Fibre - Speed Issues - Lack of Understanding by PN

Hi Phil,

I only have modem stats from after I replaced the BT modem, after the 1st BT Engineer suggested it. 

Current Rate Kbps   - Up = 6879 Down = 34999 - This has remained fixed since first installed !

Max Rate      Kbps   - Up = 6879 Down = 42384 - This does vary depending on rain normally > 44000Kbps

SNR Margin (dB)     - Up = 6.2    Down = 9.7      - This too varies it's usually about 15 when not raining

Line Attenuation dB - Up = 46.3  Down = 19.9    - I think this too is normally a bit lower

Errors (pkts)             = 0

Can't tell if Interleaving has been enabled and as it has been over a month since I switch modems and I have tried to avoid restarting or disconnecting it, I had hoped that the DLM would have recovered by now.

I had a similar issue a few years ago, but after complaining to Ofcom & BT's MD a regional engineer was allocated to resolve the issue, he replaced my feed from the pole and put me on a different pair back to the box. From that point until 1st April I was able to download at 35.8Mbps.

I suspect that unbeknownst to me I have been switched back to the duff line which also suffers when it rains.

Although if you look at the SamKnows graph you can see that the line has been becoming more unstable over the last 6 months.

Phill
Hooked
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Registered: 31-05-2017

Re: Fibre - Speed Issues - Lack of Understanding by PN

Ahh ok. I'm lucky enough to beable to get my stats from the router (you could on the TP-Link if you hacked it):

 

> vdsl status

  ---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
   Running Mode            :      17A       State                : SHOWTIME
   DS Actual Rate          : 49705000 bps   US Actual Rate       : 19585000 bps
   DS Attainable Rate      : 56603616 bps   US Attainable Rate   : 19541472 bps
   DS Path Mode            :  Interleave    US Path Mode         :        Fast 
   DS Interleave Depth     :      724       US Interleave Depth  :        1 
   NE Current Attenuation  :       19 dB    Cur SNR Margin       :        5  dB
   DS actual PSD           :     7. 2 dB    US actual PSD        :    12. 4  dB
   NE CRC Count            :        3       FE CRC Count         :     1923
   NE ES Count             :        1       FE  ES Count         :     1713
   Xdsl Reset Times        :        0       Xdsl Link  Times     :        2
   ITU Version[0]          : 00000000       ITU Version[1]       : 00000000
   VDSL Firmware Version   : 05-07-04-03-00-07   [with Vectoring support] 
   Power Management Mode   : DSL_G997_PMS_L0 
   Test Mode               : DISABLE 
  -------------------------------- ATU-C Info ---------------------------------
   Far Current Attenuation :       25 dB    Far SNR Margin       :        6  dB
   CO ITU Version[0]       : b5004946       CO ITU Version[1]    : 544ed086
   DSLAM CHIPSET VENDOR    : < IFTN >
>  

 

9CFqZNWyz1.png

As you can see i'm interleaved at the minute on downstream but it was syncing at 72 on Fastpath! My line is new and i've been messing with settings which may have caused interleaving to be enabled due to many reboots. I'm hoping after several weeks of stability it will go back to fastpath.

 

 

 

This is what i've learned in the short time of having FTTC:

 

  • PlusNet have no control over DLM
  • DLM/Profile will only be reset by OpenReach if a fault is found
  • DLM can change your line at any point 
  • Errors can cause the Interleaving level to go up and down if it's activated
  • FEC errors are not accounted for by DLM
  • CRC errors can cause DLM to act harshly if the number increments too quickly

 

 

The end result is PlusNet have no powers to do anything with your line that can result in better sync speeds. Same as other providers. They have limited info on your line and have very limited info on the DLM algorithms. 

plittlefield
Grafter
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Registered: 10-10-2016

Re: Fibre - Speed Issues - Lack of Understanding by PN

Well, now this is VERY interesting.

I too have noticed a distinct drop in Fibre speed since April.

We moved in to our house in October and used to get a steady speed of around 56Mb... not great when you're paying for the Plusnet Fibre Plus "up to 80Mb" service but we thought that's OK, and better than 40Mb fibre.

At some point in April, we noticed a speed drop down to around 45Mb, and then down to 42Mb in May.

I have been tracking my speed using SNMP and Grafana and it's sliding down each month... currently at 38Mb!

Could it be to do with the new "improvements" made?

"Data usage is no longer fully accurate. We've made some improvements to our network which will improve your connection to some popular high bandwidth services such as YouTube and Netflix. We will no longer be able to track your usage on these services which means the information below will not accurately reflect your usage."

I would appreciate any thoughts or comments please...

...because right now, I am not impressed.

RichardB
Pro
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Re: Fibre - Speed Issues - Lack of Understanding by PN

To be honest these synch speed reductions are almost certainly caused by crosstalk on to your telephone line from other fibre customers lines.

Crosstalk is an inherent problem for copper based broadband delivery. The lines are copper from the FTTC cabinets to our houses.

The more customers that sign up for VDSL then more crosstalk occurs and the synch speeds reduce to maintain an acceptable error rate.

However, we all want cheap broadband and FTTC is the cheapest way to deliver better speeds than ADSL.

Richard

 

 

plittlefield
Grafter
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Registered: 10-10-2016

Re: Fibre - Speed Issues - Lack of Understanding by PN

I have to agree with you.

I believe our overall connection speed reduction during the last few months is because of the extra vdsl customers in our local area.

We have dropped from 60Mb to 38Mb.

There is nothing I can do to improve it, so unfortunatelty for Plus Net we will be downgrading our product to the "up to 38Mbps" product.

Ho hum.

Superuser
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Re: Fibre - Speed Issues - Lack of Understanding by PN

There is nothing I can do to improve it, so unfortunatelty for Plus Net we will be downgrading our product to the "up to 38Mbps" product.

Be aware that product will reduce your upload speed to a maximum of 2Mb

Community Gaffer
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Re: Fibre - Speed Issues - Lack of Understanding by PN

@plittlefield

 

If your line is now connecting at 38Mb/s then that's a fault as your estimates are still:

 

Featured Products

Downstream Line Rate(Mbps)

Upstream Line Rate(Mbps)

Downstream Handback Threshold(Mbps)

WBC FTTC Availability Date

WBC SOGEA Availability Date

WBC FTTC 18x2 Provide Availability

WBC FTTC 18x2 Sim Availability

Left in Jumper

  High Low High Low        
VDSL Range A (Clean) 80 61.8 20 18.6 55 Available -- -- -- --

 

Testing your line is showing that it's in sync at 42.1Mb/s, so quite far below the estimates. I can see you've reported a fault to us so I'll get that updated shortly.

If this post resolved your issue please click the 'This fixed my problem' button
 Chris Parr
 Plusnet Staff
plittlefield
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Re: Fibre - Speed Issues - Lack of Understanding by PN

Thanks Chris.

daveg6hni
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Registered: 07-01-2009

Re: Fibre - Speed Issues - Lack of Understanding by PN

While I can accept that over time my speed may reduce gradually, as more & more users come on line, but that does not explain why for 3 years I was able to download at 35.8Mbps then overnight on 1st April it suddenly dropped to less than 28Mbps ?

All Plus Net say is it is within the acceptable limits for my line and totally ignore or avoid explaining why it dropped by 20% overnight ! ?

So either they are incapable of, or can't be bothered, to actually carry out a proper fault finding repair.

Community Gaffer
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Re: Fibre - Speed Issues - Lack of Understanding by PN


As previously mentioned, because the line is still within the estimates this is not deemed to be a fault by our suppliers so any fault reported would be pushed back to us immediately.

If this post resolved your issue please click the 'This fixed my problem' button
 Chris Parr
 Plusnet Staff