topic Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £ in Full Fibre

Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £65.

Youngsie97 — Sun, 16 Feb 2020 17:22:12 GMT

I am seeing high pings in the 80s for connecting to uk services and noticed that interleaving was enabled for downstream with a depth of 963.

I phoned yesterday and asked for interleaving on my downstream to be disabled(I believe this is possible?) and was told no problems it had been submitted and would take four hours to procress and to reset modem and router by unplugging replugging etc.

Did that left it until today and it is still on interleaving 963 so I phoned again today and spoke to somebody who openly admitted she hadn't done it before which is fair enough its not a "normal" thing to be asked.

Cut into 15 minutes later and I was told she was unable to process it as it wasn't going through but she had been asked by somebody in the faults department how I could see this because they cant see interleave stats from their tests on a vdsl line?.

TLDR they want me to pay £65 for an engineer visit for the engineer to disable interleaving. I don't believe this is correct. So came here to request interleaving be turned off on my connection once again and if possible a DLM reset.

I am aware a dlm-reset has to be triggered by an openreach engineer but shouldn't require a visit...

Thanks

-Connor

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Gandalf — Sun, 16 Feb 2020 18:56:42 GMT

Hi Connor, Sorry for the issues you're going through to get interleaving switched off. Unfortunately there appears to be a bit of a knowledge gap with the advisers you've spoken to, because on fibre it's not possible for us to request adjustments to the settings of a DLM profile unless a line speed is restricted by a 'banding' where we'd request a remote DLM reset which is a manual process done by the Openreach diagnostics team.

The potential engineer charge of £65 you've been quoted wouldn't be for interleaving to be removed, it's if an engineer finds no fault with the service or the problem is with your equipment. I'm afraid we can't send an engineer to solely carry out a DLM reset to remove interleaving, when we arrange engineers it's part of an investigation for example your connection may be dropping or speeds below where they should be.

Poor latency isn't considered a fault by our suppliers, it's generally a symptom of another issue although a ping of 80ms I'd say is fine unless it's spiking all over the place. Are you experiencing any perfomance issues with your service that's prompting this?

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Sun, 16 Feb 2020 19:38:43 GMT

Last week my speeds dropped to 39 Mbps and my ping spiked.

I decided to go out and a buy draytek vigor 130 modem to replace the open reach modem feeding to my pf sense box. so I could see line stats.

I tweaked my snr a bit and managed to get my speeds back to 52-56 which I am happy enough with.

However when I have two lines to the property and one pings at 25 and the other 80 (in 2020) im sorry but thats anything but "fine".

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Gandalf — Sun, 16 Feb 2020 19:43:40 GMT

Thanks for the detail. While I understand what you've said, as a service provider we've no control over interleaving as that's handled by DLM which is in the domain of Openreach and our suppliers don't consider latency issues a fault.

Again high latency is normally a symptom rather than a cause, what performance issues is this causing you? Perhaps we can help with that.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Sun, 16 Feb 2020 20:37:14 GMT

Thanks for your help Gandalf I think my confusion comes from the fact that you were able to control it on ADSL lines. I guess open reach has extended their grasp around the necks of british ISPS!.

My only really issue with my service is higher than usual latency right now than the past couple of months but I am hoping DLM will do its job and restore order before too long (Again would love a DLM Reset but I appreciate you arent authorized to issue a request to the overlords without a "valid" reason).

As I don't really have the time to diagnose the issue right now and plusnet are technically within their contract by providing me 56 down (although sky provide 76 to the same property) I am happy to just move on for now and hope DLM sorts the connection out.

Interestingly interleaving is off for my upstream!

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Gandalf — Mon, 17 Feb 2020 12:06:23 GMT

No problem Connor. Yeah we can still control this on ADSL because as far as I'm aware the DLM for ADSL is under BT's control and we've been given the right tools for this. For fibre, the DLM is all under Openreach's domain.

I've checked your line and as of yesterday the DLM profile is showing at: "Downstream: 0.128M-80M with Interleaving (Low). Upstream: 0.128M-20M with no error protection" so there is definitely interleaving on the downstream.

Looking at your speeds while they're at the very bottom of the speed estimates/expectations of your line between 65mbps and 80mbps, our RRT(Reactive Repair Tool) data (It's not as repairy as you'd think, it's just for diagnostics we can't change anything using it) is showing your line should be able to perform better.

I can see in the past 14 days your speeds have declined from 68.17mbps to around 61.78mbps with interleaving enabled in a high mode at the beginning of this period, and it's now in a low mode so hopefully with time the DLM will remove interleaving altogether on the downstream.

Based on this and that you've tweaked the SNR to try to artificially boost your speeds, I think there's an underlying fault here. When you've got time it may be worth running through the steps Here to connect your router into the test socket behind the faceplate of the master phone socket to rule out any issues with the internal wiring of the property.

If there are no improvements, I'd recommend raising a fault to us online at https://faults.plus.net posting back afterwards so we can arrange an engineer visit to investigate further.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Tue, 18 Feb 2020 00:02:45 GMT

I had noticed my quality degrade recently which is part of the reason I switched modem but I have so much custom configuration going on I put it down to that. I am okay with my connection being slightly less than great I am not okay with potentially paying an open reach engineer £60 if they decide my equipment is at fault.

I am running a draytek vigor 130 into a pf-sense box with plusnet as the gateway and two vpns running on layer 3. I was getting quite bad bufferbloat so i have speed limiting setup in pf-sense to limit me to about 62mbps to resolve the bufferbloat issue. I then have a block of ipv4 addressess that route over the plusnet gateway to aleviate ping problems when gaming(I have also disabled the vpn clients and traffic limiting to see if it resolves ping issues it did not. and buffer bloat comes back massively.).

The earliest i would be able to mess with things including plugging into the test socket would be wednesday.

Interesntingly the tech support on the phone said they couldn't even view the DLM profile of a VDSL line so certaintly some miss information being spread ;).

TLDR I have a heavy setup and won't be able to tinker with things until wednesday at the earliest.

PS: I know its not an excact number but how many FEC and CRC errors should one expect to see on a "healthy" line? over a 24 hour peroid?

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Gandalf — Tue, 18 Feb 2020 11:21:26 GMT

When you've got a chance, to rule out your equipment it may be worth disconnecting that and connecting the router we've sent into the test socket, which would kill two birds with one stone in effect (Disclaimer, no actual birds will be harmed )

With regards to the mis-information, it seems more of a knowledge gap but I believe they've since had clarification by liaising with one of their colleagues.

We don't really see FEC or CRC errors on our testing as they're generally not that relevant to us. As far as I understand them they're a by-product of errored seconds, FEC errors being errors that have been corrected (likely by interleaving or another form of error correction), so a large amount of these alone isn't anything to worry about.

CRC errors on the other hand are the opposite in the way that a large amount are bad, but it's also similar in the way that they don't really tell us much as there's a lot more factors which can cause them. I find that the Kitz website is a pretty good knowledge base, particularly here may give a better explanation and some more detail.

What I'd look out for are Errored Seconds(ES) or Severely Errored Seconds(SES). I've attached a graph below of the mean time between errors (MTBE) showing that your line appears to have been erroring fairly badly on the downstream.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Tue, 18 Feb 2020 16:28:32 GMT

I meant to add onto my last post that I would swap out equipment for default when testing the test socket and during the duration of the open reach visit if one is required but i was tired and must have deleted it!.

I am not 100% sure when I switched my modem out ( i want to say friday?) but when i initally my snr noise margin to -50 db which did more harm than good in the end as I saw something like 68810 es in a day.

Since reducing it to -25 setting my snr margin to 3db i have since seen 166 es out of 80194 es so a much better ammount ;).

I must admit line errors and terminology is all a bit above my head at the minute but the whole reason I bought my plusnet line was so I could setup pf-sense and mess about and learn things so its serving its purpose atm (Family would not be happy if i tinkered with main line and booted everybody offline 😉).

TLDR. I will begin messing with things tomorrow including plugging the hub one in to the test socket and I assume I would just run speedtests, ping tests traceroutes etc to see if the connection is faster?

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

kitz — Tue, 18 Feb 2020 17:52:56 GMT

Unlike with ADSL they can't just click a button and it all goes through automatically.
With VDSL lines it is possible to get a DLM reset only under certain circumstances. This process is a wee bit more manual and the line must meet certain criteria such as appear to be stuck and/or the line must have been stable again for a reasonable period.   iirc in the original instructions to the SP's Openreach during the trial would be doing random checks to ensure SP's weren't just requesting resets without due cause.

If the line has had Error Protection (& Interleaving) applied, then in theory if the line is stable then it should return back to Error Protection off within a certain timeframe.   How soon it returns depends upon whether Error Protection has been applied in the past.   If its a first offence then usually within a few days of stability. For each offence the time scale of required stability goes up eg 5 days, 10 days, 14 days, 6 weeks. {can't recall exact dates off the top of my head but something like}

However, we have noticed recently that some [ECI] lines are having Interleave applied despite not getting anywhere near the usual 2880 E/S per day.    I got Interleaved last Oct for just 25 Err Secs which was a short spike of CRCs lasting less than a minute.   6 weeks later despite having less than 10 E/Secs per day I was still Interleaved.
A request for DLM reset was approved as I had gone over 6wks with an ILQ green status.

I tweaked my snr a bit and managed to get my speeds back to 52-56 which I am happy enough with.

Not such a good idea with the Openreach NGA DLM. 😕 Lower SNRM means more likelyhood of errors and much longer for the DLM to remove interleaving under its own steam. The only way we have had some sort of sucess to getting the DLM to relent faster is by capping the linespeed to give it alower sync and higher Noise Margin

Interestingly interleaving is off for my upstream!

Upstream and downstream are treated independantly of each other. Its not unusual for it just to be on the downstream or even vice versa.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Gandalf — Tue, 18 Feb 2020 17:59:18 GMT

Thanks for the post back @Youngsie97

Ah sounds good, no problem I live in a shared house so I know the feeling when you go messing around with the internet. Yeah I'd just run speed tests and trace-routes (a good one is pingbox1.thinkbroadband.com) although once you've made the changes if you don't notice any improvement, let me know as your speed may be restricted by profiling on our side.

There's basically a profile on an account from a bygone era which should always sit below the current sync speed but when the sync speed changes, the profile can be a bit slow to adjust and will restrict your throughput/download speed if set too low. The majority of connections ignore whatever this profile is set at but on a small number, generally when you have a static IP, does the profile have an effect if too low.

Let me know how it goes.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

kitz — Tue, 18 Feb 2020 18:12:03 GMT

btw and MBTE of >5000 is good, as it means ~18 Err/Secs per whole 24hr (86400 secs) period of uptime.

MTBE is the average time between errors occuring and is calculated as follows:

MTBE = Connection uptime / Code Violations (Errors)

So usually, the higher the MTBE, the better the line.

A good line (is/was) categorised as ILQ green if it has an MTBE >300 on the speed stability profile or >600 for standard profile.
A bad line (is/was) categorised as ILQ red if it has an MTBE <30 on the speed stability profile or <60 for standard profile.

Based on the previously known speed profile:
MTBE of 300 = apprx 279 E/Sec per full 24hr of uptime = ILQ Green
MTBE of 30 = apprx 2880 E/Sec per full 24hr of uptime = ILQ Red
Anything inbetween those 2 figures = ILQ Amber

Back to that HOWEVER above.
Note I say (was) because after some digging Openreach have indeed been tweaking and changed something since Sept last year. Exactly what, I can't quite fathom out yet... from the limited info it may be recording different time value MBTE than 24hr... or even taking into account massive CRC spikes which run into thousands.

@Gandalf would you like to do me a massive favour please and show the my graph for my vdsl line.
I may be able to get a clue from comparing my linestats to their graph... as I've got some regular daily periods of SHINE-like CRCs over the past few days so it would be an ideal opportunity to see if it is doing anything with those.

Cheers

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Gandalf — Tue, 18 Feb 2020 18:33:02 GMT

@kitz Yep sure thing and thanks for posting btw.

Took me a while to find your account, I've attached the graph below:

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

kitz — Tue, 18 Feb 2020 19:06:07 GMT

Thank you muchly. I'll do a compare later.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Wed, 19 Feb 2020 17:20:47 GMT

I plugged my modem into the test socket today and turned all vpn clients and traffic control off in pf-sense. my line was syncing at 66 but I was still only able to get 61mbps and buffer bloat of grade b according to dslreports.com

I tried to plug in the plusnet hub one but despite having two routers I couldn't find a power plug and all my others were only rated to 12 v 1a and didnt fit.

my friend has recently switched from plusnet to ee(his cab can get 120MB/s (despite only being 5 mins up the road of me.. I am not jealous at all...)) so I will ask him if he still has power plug when he gets off work tonight.

Ping stayed in the same range of about 18-20 to bbc.co.uk which is about 7 more than my other line so thats okayish.

I am inclined to say that using the test socket didn't make a difference but will do some more tests and report back.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

kitz — Wed, 19 Feb 2020 17:27:37 GMT

Update

Analysis of data from the graph would seem to infer that the MBTE data held in the DLM records more or less ties up with MTBE calculations made from my linestats using the last known MBTE parameters.
All days bar one were within 1 or 2 Err/Secs, which considering I was taking data from a graph to the nearest 50 MTBE value, is possibly about as good as you can get without actual data set numbers to be able to confirm DLM is just using Err Secs on a non G.inp line.

The only day with a noticeable discepancy was 27th Jan, where the graph shows MTBE 3500 yet my stats calculation was 1630. There were 0 SES that day and no unusual CRCs aside from the brief daily SHINE spike. This would infer my modem recorded more E/s than DLM did so I'm not going to worry about it as it was in my favour. Perhaps part of the days data wasn't captured, as I notice the 25th had no data captured at all. **

--------
ETA - Just had a thought, the fact that my modem recorded more errors than DLM - could be attributed to the fact some data was discarded due to a Wide Area Event.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

kitz — Thu, 20 Feb 2020 01:27:38 GMT

>> 68810 es in a day.

Wow!! I just noticed that figure 😮. I don't think I've ever seen that many before. The max is 86,400 but that would be on a permanently erroring line!
I'm not surprised the DLM took notice of your line. 2880 E/S per full 24hr period is enough to put you at ILQ red. The line must have been running like a pile of poo. 😕

Just checking if you realise too many coding violations (eg CRCs) will cause your latency to go completely to pot?

In very simplistic terms a CRC is a corrupt data packet which has to be resent and E/S is a counter of each second which contained a CRC. Tweaking your SNRM too low may well appear to increase your sync speed, but it can come at a huge cost to signal strength and noise on the line. There is no point in opening up more channel frequencies when the additional noise is going to cause dropped packets and delays.

Delays from dropped packets have a far worse effect on latency than interleaving does.
Low Interleave adds just 8ms. High Interleave adds 16ms. If you are seeing a higher increase than that, then its likely to be delay from some other source.

tldr; Do not tweak your target SNRM too low. It will not only cause instability & errors but it will also effect your latency.

----------------------

The theory is that for interleaving to be removed, you need to keep the purple line on your graph which Anoush showed you above MTBE 300 for a certain period (days).
MTBE 300 = 280 E/Sec per full 24hr period.

DLM needs to see your line running for a period of time with hardly any E/Secs. Bearing in mind that the line now has Error Protection and Interleaving then the DLM will expect to see very few E/Secs anyhow.

Whilst we talk about E/Secs you must remember that DLM judges the stability of your line based on MTBE (the average mean time between E/Sec over the course of the day). Therefore:-
High E/Secs figure = bad.
Very low MTBE = bad.

>> plugging the hub one in to the test socket and I assume I would just run speedtests, ping tests traceroutes etc to see if the connection is faster?

Linestats are the best way of checking. The Hub One provides only limited stats, but it does show the sync speed (the speed you connect at) which is the important one. iirc the HubOne displays this as the Data Rate. Unfortunately I don't think it shows Err/Secs - but the good thing is that you cant tweak your SNRM down to cause additional errors

How to get stats from the Hub One

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Thu, 20 Feb 2020 02:32:48 GMT

I have been plugged into the test socket most of the day as some important work came up I had to do and I forgot about it. just checked my line stats and ouch!.

noticed

Mate was't able to find his plug so havent tested the hub one yet. going to undo the snr tweaks I did and plug back into the normal socket as I have noticed a bunch of issues with my connection today. And not surprising with 446 SES .... (I havent renablled my trafic shaping and limiting again yet so could be caused by buffer bloat maybe??)

I was seeing about 15 ES an hour yesterday when plugged into normal socket.. and no ses.

I understand the basic Concepts like CRC errors etc. I have novice to intertmediate networking knowledge just in the dark as to DLM voodo . My speed seems hard locked to 61 Mbps down regardless of sync anyway. (banded?).

Sadly I have a bunch of assignments for uni due atm so my time for tinkering is limited.

PS. Your assistance so far is appreicated thanks kitz and Gandalf(sorry on a thinkpad x220 with a 1366x768 12" screen and I am not scrolling up to find your name so you shall remain Gandalf for now) .

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Thu, 20 Feb 2020 03:02:50 GMT

Back into normal socket and snr margin delta is now 0 so snr margin is now 6

DSL	Connected : Down Stream : 58570Kbps / Up Stream : 17469Kbps

I have lost about half a MB in download speed which is a shame. I shall keep an eye on error counts and see how things goes.

Downloading at 5.9-6.2MB/s atm but pf-sense is showing 1% packet loss on WAN whilst downloading.

Re: Was told for interleaving to be disabled on a VDSL line i would need an engineer visit costing £

Youngsie97 — Thu, 20 Feb 2020 04:35:17 GMT

Apologies for tripple posting in one night but I had completey forgotten that i set up a cronjob about a year ago to create a sort of data is beautiful piece by running a speedtest on the hour every hour my machine was on.

You can see the trend of my ping get higher from the end of january.

Its not conclusive because i am connected to a vpn for 95% of those tests. (fair warning theres over 4400 speed test results) and obviously the vpn servers could be having issues blah blah but here it is anyway.

I have no idea what I was intending to do with this data as obviously its not very easy to graph 4400 data points.

that being said heres what a weird graph based on download speed looks like.