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[b4z]

Question to you guys, what could be the cause of this rather large Downstream rate drop?

Same address.
Same line.
Same hardware. [HG612]
No changes.

August 2016
ISP: BT Broadband [55/10]
Max:   Upstream rate = 32727 Kbps, Downstream rate = 93504 Kbps
Bearer:   0, Upstream rate = 9999 Kbps, Downstream rate = 55000 Kbps
      Down       Up
SNR (dB):    17.3          22.9
Attn(dB):    10.8          0.0
Pwr(dBm):   13.5         -3.4


March 2018
ISP: Vodafone [80/20]
Max:   Upstream rate = 31589 Kbps, Downstream rate = 68376 Kbps
Bearer:   0, Upstream rate = 20000 Kbps, Downstream rate = 68654 Kbps
      Down      Up
SNR (dB):    6.3       13.4
Attn(dB):    10.5       0.0
Pwr(dBm):    13.4      -4.3


So i contact Vodafone, ask them to contact Openreach to perform a 'Remote DLM Reset' as per;
https://www.ispreview.co.uk/index.php/2018/02/ability-reset-openreach-fttc-broadband-dlm-profiles-arrives.html

Openreach tells Vodafone to tell me to, and i quote, "unplug the cable from the master socket to the modem/router, then plug it back in" and that should work.

I find that suggestion to be total nonsense, lazy and disingenuous.
And so I have filed a complaint with Openreach via their website.

As per the article above, the process seems to be as follows: ISP submits lines to be reset, Openreach compiles them into a list, and at 00:00 that evening all the lines on the list get a remote dlm reset.

Openreach are seemingly refusing to cooperate with Vodafone on a process (they have just made available) that saves them time/money/engineer visits etc.

[Update: See further down the thread - Vodafone lied to me/fobbed me off, Openreach are not at fault/responsible]

[Ixel]

One idea that comes to mind is crosstalk, however with so little stats to work on it's hard to say . Maybe someone else here has a better idea. Looking at what you've posted I don't believe a DLM reset will achieve anything as your downstream sync speed is already around the maximum attainable speed for the downstream and so Openreach would probably reject it.

It may be a good idea to post your current full stats assuming that's possible, as well as a Hlog and QLN graph.

[kitz]

Openreach tells Vodafone to tell me to, and i quote, "unplug the cable from the master socket to the modem/router, then plug it back in" and that should work.

That doesn't sound quite right to me.   
Procedure is that the ISP must perform some basic tests before submitting a call out to Openreach.   It sounds more like one of Vodafones suggestions that go in the same category as "Are you connecting to the master socket".   If Vodafone placed a fault report with Openreach, then an Openreach wouldn't sent that message back..  they'd send out an Engineer.

There is also a strict criteria which must apply before your ISP can request a reset.    One of them being the ISP must check that there would be an improvement on the line of 'x' amount..  your's doesnt have any room for improvement.
Finally..   the  reset proceedure is a "One Shot attempt".   Openreach never give any feed-back to the ISP... ever.

So i contact Vodafone, ask them to contact Openreach to perform a 'Remote DLM Reset' as per;

Not sure if a reset would achieve anything. 
- Your SNRM is 6.3dB - which is the standard Target SNRM and there is nothing left in the line to give you any more speed.   
- You're syncing at 68654 and max is 68376...  therefore it doesnt look like the line is interleaved.
Thus all indications are that DLM is running at the standard profile without any action that could benefit you if the line is reset.     

In fact performing a DLM reset may see your line-speed drop further...  as default profile after a reset would apply interleaving. 

what could be the cause of this rather large Downstream rate drop?

As Ixel has already mentioned... it will be cross-talk.     Most of us have lost large amounts of speed over the past few years due to cross-talk.
I've lost nrly 40Mbps from my headline speed since I first got VDSL.  A loss of 20-30 Mbps is the norm.

[kitz]

And so I have filed a complaint with Openreach via their website.

Which in a way is unfair.   Because it honestly does not sound like the sort of thing which Openreach would have done


DLM reset requests don't work that way.      Your name gets added to a list, which gets emailed to Openreach and the reset gets done or it doesnt.   
Even if it doesn't get done, then there is no feed back at all to the ISP.
   
Sounds more like something Vodafone have come up with..  but Vodafone should have checked first to see if a reset would improve the line whilst you were on the phone with them.

One of the concerns about making info such as the DLM reset being available was that EU's would start insisting on them for no benefit ... or that ISP's would start abusing the reset as a 'magic fix' which wouldn't actually achieve anything.   

If I were to guess what really happened is I'd say that either
1) Whoever you requested the reset from said OK, then someone higher up at Vodafone spotted that there wasn't anything more in the line, so Voda concocted this story to feed back to you   OR
2) The request was passed on to Openreach, who would have just dropped it because it didn't fall within the improvement criteria.   A few days later someone at vodafone noticed nothing had been done and then realised it didnt fall within criteria and made up a convo to feed back to yourself.

How soon did they report back to you supposedly what Openreach said to you?   That should give an indication of which scenario occurred.

[j0hn]

Looks like crosstalk to me.
A DLM reset will make no difference. There appears to be no DLM restrictions in place that are limiting the line.

Vodafone sound line they are fobbing you off with the message they gave you. A DLM reset really will make no difference though. The only thing that could help is an on site engineer checking the line, perhaps a doing a pair swap. An engineer won't do this without a specific request from the ISP though.

Has the drop been gradual, or all at once? Looks to big a drop to be a single crosstalker. It's well within the range of multiple crosstalkers over a period of time.
It's just the nature of the technology and nothing that can be done without vectoring.

[b4z]

The initial enounter i was describing: It was on a live phone call with Vodafone. I was on hold for over 30 minutes whilst he tried to contact Openreach.
So i guess i am to assume the Vodafone representative just concocted that story and didn't even get in touch with them.
Unbelievable if so...

It is only recently within the past 1 month or so that the "Attainable Rate" has dropped significantly. Before that it was above 80000 kbps.

I think the line is interleaved as per the HG612 Modem Stats screenshot from today attached.

I have also attached the line stats from 16:00 today.

I can provide more information if helpful/necessary.

Thank you

UPDATE:

I decided to recontact Vodafone, i encountered a more helpful and useful person this time from "First Line Support" they ran a test and told me this is what returned;
Red Flagged, "Network Capacity Error", Openreach Engineer Required
They have referred me to "Second Line Support" (more advanced diagnostics) who will conduct further tests and contact me within 48 hours. They will notify me if an Engineer appointment is booked etc.

So my next question is what defines a "Network Capacity Error"

[jelv]

Let's just back up a bit. Are you having an issue with your actual download speed being a lot slower than your current 68654 Kbps sync speed, and is that what caused you to investigate and post the data in your initial post?

[b4z]

I am just trying to find out the reason why my line was capable of an Attainable Rate of 93504~ Kbps but is now (supposedly) only capable of 68376~ Kbps and seemingly keeps degrading.

I had a Sync Rate of 79999 only a month or two ago. I can remember that much from when i was looking via the dslstats software.

Could this simply be because of Interleaving?

Could the Interleaving be enabled because of some issue at the Cabinet or Exchange?

[ejs]

You lines stats indicate you have G.INP (and its insignificant amount of interleaving that is used with G.INP on Huawei cabinets), you don't have any significant amount of interleaving.

The non-G.INP interleaving tends to make the attainable rate calculated significantly higher than the actual rate possible. You don't have that issue.

[jelv]

If you are not seeing actual speeds reduced I'm struggling to understand the relevance of

Red Flagged, "Network Capacity Error", Openreach Engineer Required

[Black Sheep]

If you are not seeing actual speeds reduced I'm struggling to understand the relevance of

Red Flagged, "Network Capacity Error", Openreach Engineer Required

Me too. I don't even know what that term relates to either, in this particular instance ??  Is it a posh way of saying, 'crosstalk' ??

[kitz]

Me too. I don't even know what that term relates to either, in this particular instance ??  Is it a posh way of saying, 'crosstalk' ??

No. Network Capacity Error is congestion.   It looks like Vodafones equivalent to a BTw Hot VP/SVLAN.

I'm therefore puzzled why or how Network Capacity could be fixed by an Openreach Engineer. 

[Black Sheep]

No. Network Capacity Error is congestion.   It looks like Vodafones equivalent to a BTw Hot VP/SVLAN.

I'm therefore puzzled why or how Network Capacity could be fixed by an Openreach Engineer. 

Yeah, that's my point exactly, kitz ............ that's why I wondered if, (bizarrely) they might have similar wording for 'crosstalk' with the mention of an OR engineer ?

Cable-fill = Network capacity error ....... obviously, this was an extremely long shot. 

[kitz]

I'm seriously beginning to doubt that they know what you are requesting with a DLM reset.

---

What you were told the first time around doesnt make sense to me, the fact that you were on hold while they tried to contact Openreach I'm afraid does not ring true.    They cannot contact Openreach to have a telephone conversation with them like that.

DLM reset requests are only currently done by e-mail to a specific department.  Openreach just will not enter into any correspondence, nvm telephone call about DLM resets.    I'm afraid it really does look like the first person fobbed you off and tried to put the blame on Openreach.

You were possibly kept on hold whilst they tried to find out what it was you were requesting.

---
The second response doesnt make sense either. 
Sounds like 'First Line Support' ran diagnostics and it flagged up on their system there is a capacity error on their backhaul.   That red flag is supposed to be there so that if the EU is complaining of slow speeds then they know its likely down to capacity issues on their backhaul.

-------


I'm beginning to have a niggling doubt over this, because they really don't appear to understand what you are asking for.       
AIUI 1st stage trialists were Sky & TT - I dropped plenty of hints last year that it was just a couple of GEA SPs.   
Last month it was extended to BT Wholesale... and therefore now included ISPs such as BTr, Plusnet, AAISP etc.

Has anyone ever seen a Vodafone customer get an FTTC DLM reset?  Are Vodafone actually partaking in the interim solution yet?
If they are...  then someone @ Vodafone should have spotted straight away that your line doesnt meet the criteria for a DLM reset (as there is insufficient room for improvement based on your linestats.)

[NewtronStar]

I suppose the OR Engineer could do one of those pair swaps to remove possible crosstalk for a short period, until a new customer come online then crosstalk on to that new pair.