Plusnet deliberatly slowing my speed!!!!!!

[#1]

After years of slow internet due to the distance between me and the exchange, (was getting between .025 and 0.4 Mbps) I decided to buy a new router designed for long lines (BT Business hub 2700 HGV).  This increased my speed almost overnight to around 1 Mbps.  however, somebody at Plusnet must have noticed this and decided to slow me down by turning interleaving on despite having a very stable connection.  This reduced my speed back to around 0.4 Mbps.  After 3 weeks of phone cals and e-mails, I finally got interleaving turned off.  My speed should now go back to what it was right? WRONG!!!!! After turning off interleaving, to make sure that I didn't get the speed I should get, they capped my rate.  I have spoken to them several times now and have been told  a different story every time ranging from 'your rate is not capped' to 'I will request that the cap be removed but this will take up to 72 Hrs'.  72Hrs after this one I checked and guess what, still capped.  All I get from CS now is 'we did not do this on purpose, why would we?'  I don't know why you would but the fact remains, YOU HAVE DONE!!!!!!  It has now been a month of unusable internet and I have refused to pay my next bill as they have interfeered with my settings and taken away my browsing/surfing ability.

[#2]

First, Plusnet have no control over your sync rate, line condition, speed banding, IP profile or turning interleaving on or off... this is all being done by the automated systems at the exchange (called DLM or Dynamic Line Management), so blaming Plusnet for something they have no control over is wrong...
However, they are still supplying your broadband connection and should do as much as possible to ensure you have the best speed possible for your line conditions but they, like most other ISPs that use IPStream connections are at the whim of the exchange. Each time they need to make a change they have to submit a request to BT who in turn eithe process the request, or often bounce it back or ignore it.
Given your speed you are either on a very bad line or are a long way from the exchange... in this situation the DLM does not always work in your favour, especially if you disconnect (for whatever reason) which can often be seen as a problem which the exchange tries to solve by adding interleaving or fixing the speed. You are unfortunately one of those users who's line tends to cause lots of issues with the exchange and I suspect, no matter what Plusnet do, the exchange will always decide the best solution (in its view, often not in your favour)  regardless of what was previous set or requested by Plusnet.
DLM is never going to be good on your line.

[#3]

I am on a very long line but was getting around 1 Mbps before this issue started.  If Plusnet have no control over it as you say,  Why did the CS agent say they would look into why they had done it?  Not one of the tech support people I have spoken to has mentioned anything about an automated service at the exchange.  I'm not saying that this is not what is causing it, but if it was, why has nobody mentioned this before.  They have practically admitted that it was them that altered the settings.  I am only with Plusnet for about another month until I move on to satellite broadband but do not hold my breath for them to fix the problems before I leave. (Although as I only have to give 10 days notice, I have not officially canceled my service yet).

[#4]

I guess, following the principle that PN must take responsibility for whatever "their supplier" does to the line, you can quite easily understand why CSC would look into "why they had done it" - when they really understand it to means "why we or our supplier had done it".
At a tech-level, DLM is well understood to exist, but there are conflicting reports about the way it works, and its impact - including contradictory information from BT. To be honest, it probably isn't a surprise that CSC didn't try to explain the intricacies of DLM to a customer. It isn't an explanation I think I'd embark on unless I understood the customer was techie-inclined.
As Peter said, Plusnet have no ability to alter settings on a day-to-day basis, and certainly no ability to get things changed for the worse. On 20CN, they can ask for the line to go through a new 10 day retraining period, which has the effect of setting the SNRM back to 6dB, or to turn interleaving on/off. For 21CN, they can do the same two actions, and can ask for a banded line to be reset.
But an automatic resync to slow the line down, or to turn interlaving off, is down to DLM - which means the exchange can immediately, automatically, undo a change requested by PlusNet.
When users see this happening to their internet connection, the cause often turns out to be an intermittent problem on the line, causing DSL sync disconnections. These can be a pain to work out, sometimes being quick, and sometimes seeing a number of engineer visits. Its your call as to whether you want to bother starting the fault process to trigger this work.

[#5]

BT claim that interleaving has no impact on the line rate, except for lines running at 8128 kbps (which interleaving reduces to 7616 kbps).

[#6]

Well thats a lie
I can lose around 1500mbps sync rate switching off interleaving.
adie:quote

[#7]

Quote from: Epyon

I can lose around 1500mbps sync rate switching off interleaving.

Turning interleaving off reduces the sync rate?
Perhaps on a noisy line turning interleaving off causes DLM to increase the noise margin instead; that would certainly reduce the sync rate.

[#8]

Yes
Interleaving = More speed but slower ping
Fastpath = Less speed but faster ping
DLM has not changed my SNR target.