Minimum Guaranteed Speed reduced after raising ticket and Openreach 'fixing'.

[#1]

I've been with Plusnet for quite a few years now, and when Openreach finally put in FTTC  I was even happier to change to Unlimited Fibre at the end of 2017.  This is the line speed figure I was given then:

Your line speed

We estimate your broadband speed should be between 32Mbps and 40Mbps and your minimum guaranteed access line speed is 27.6Mbps.

My actual download speeds fell nicely in the middle of those above, averaging 30-32mbps, with just a few hiccoughs along the way, and on the next renewal I was given the same figures. However the next renewal in Jan this year came with:

Here's all the speed details you need to know.

has an average speed of Mb download.

We weren't able to calculate the estimated peak-time speeds for your broadband at the point you placed the order, but we'll continue to process your order as agreed with you.

Your Minimum Guaranteed Speed wasn't available at the point you placed the order but we'll continue to place your order as agreed with you.

At the time I commented that after 20 months at the above figures, my speed was steadily dropping (I was getting occasional speed as low as 24mbps - a 20% drop! A ticket was raised, and Openreach set to work!! I had a visit from one engineer who plugged his test set in and told me I was getting much better than his test set said I should be getting, and my MGS should be around 15mbps. However he (and a further two engineers) pottered around and found a fault in their line (by now I was at 20mbps) and speed went back up to 30mbps.

However, in May it took another hit and suddenly went back down to 25 mbps, and although I raised a ticket I was told that that was the best I could expect to get according to Openreach, and it has stayed there ever since.

I'm not unhappy with Plusnet (the speed issue isn't their fault AFAIK), but on contract renewal yesterday I got the same lack of information re speeds, but my page on Plusnet broadband now shows (I wasn't quick enough to copy the original page):

Your broadband service

• Product: Unlimited Fibre
• Estimated Download Range: 24 - 37Mbps
• Estimated Upload Range: 5 - 7Mbps
• Minimum Guaranteed Speed: 19.8Mbps
• Current Line Speed (Download): 27.4Mbps

Of note the best download speed I have achieved since July is 25 mbps.

My question though - how can my Minimum Guaranteed Speed reduce by 30% in 6 months?

[#2]

In a word 'crosstalk' - have a read of this article for the full detail https://www.increasebroadbandspeed.co.uk/2014/vectoring-crosstalk-crisis 

Essentially as more people subscribe to the service from your cabinet over time crosstalk with decrease the speed you get.  When I first got FTTC I could sync at 130Mbps (although I was capped at 80Mbps), since then the line has dropped down to 65Mbps, but has now recovered as I am one of the lucky ones who benefits from vectoring.

Basically it's rubbish technology - they are pushing copper well beyond what it should be used for.  With any luck we will all get FTTP within a few years and you won't have to suffer decreasing speeds everytime someone else on your cable bundle takes a service.

[#3]

Well I'll say thank you for the less than welcome news! Although why it should suddenly drop over one week when (as far as I can find out in our small village connected to the box in question) there were no new sign ups.

[#4]

I should have said it's not just new signups that effect it. If someone regrades from say a 40 Mbps to 80 Mbps service it can change crosstalk as more noise is caused. The effect is hard to predict as it's a function of the number of subscribers in your bundle, length of line, what speed they achieve etc. I monitor my line and I can go months with no change, and then something changes and you see it drop.

[#5]

The wonders of copper cables from the cabinet. I was aware of the crosstalk potential, but didn't expect such a sudden (relatively) difference. I also monitor my line as do a lot of my neighbours - it's more interesting looking at the range of speeds we all get as well. Some of those who are closer to the cabinet (line length not crow flies) have slower speeds than others who are further away, although no one has seen much of a change over the last year apart from me.

Interestingly I've looked at asking for an 80mbps service; the BT/Openreach engineer said it was available, but Plusnet first said it wasn't, and then that I wouldn't see any change, and in fact it could go slower. I'm resigned to the lower speed now, but still feel let down somewhere along the line, and now have to get used to buffering on Netflix and other streams when there are other things going on. All I can hope for is that our village initiative to get FTTP goes ahead.

[#6]

If you are in a village with a cabinet that was paid for by BDUK funding, it's possible that you have vectoring enabled.  I also live in a village, and have a cabinet and modem (old HG 612) which supports vectoring and I get 92Mbps.  My next door neighbour (literally 10 metres away), who is also with Plusnet, uses the Hub One, which doesn't support vectoring and only gets 56Mps.

I guess it's also possible that people nearer the cabinet might have aluminium along their line path, whereas folks who are further away are on completely copper path - unfortunatly it's a bit of lottery how good your bit of copper and the joints are.

Out of interest what is your actual sync speed and attenuation (you can see it in help desk on the Hub One) ?

Re: FTTP - you may be suprised, they are installing it in our village at the moment.  Round here they seem to be installing it in all the villages.

[#7]

I don't use Hub One either- on an ASUS DSL-AC68U which gave me a much more stable connection and a marginally better speed.  Stats shown as follows (although note attenuation varies day to day). Whilst I am now on Fast Path, for a long time I was on an interleaved path mode downstream at a depth of approx 450 (IIRC) which seemed to be marginally better.

	Downstream	Upstream
TCM(Trellis Coded Modulation)	On	On
SNR Margin	6.1 dB	6.3 dB
Line Attenuation	19.7 dB	44.4 dB
Path Mode	FastPath	FastPath
Interleave Depth	1	1
Data Rate	27397 kbps	8298 kbps
Max Rate	37448 kbps	8298 kbps
Power	11.3 dbm	5.8 dbm
INP	-	0.0 symbols
INP-SHINE	43.0 symbols	-
INP-REIN	1.0 symbols	-
CRC	0	0

[#8]

You attenuation at 19.7 is only a little worse than mine at 15.3 (below), but both your D/S and U/S sync's are far worse.  I have a friend who has a 19db attenuation and gets 70Mbps so yours looks very low. 

Max: Upstream rate = 27005 Kbps, Downstream rate = 92712 Kbps
Bearer: 0, Upstream rate = 20000 Kbps, Downstream rate = 79999 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.6 10.3
Attn(dB): 15.3 0.0
Pwr(dBm): 12.6 6.8

The fact that the data rate is so much lower than the max rate is interesting - that suggests to me there was a lot of noise when you last sync'd which has now gone.

It's either a fault or crosstalk - as it looks like the ASUS DSL-AC68U supports vectoring it might be worth making sure it's turned on and G.INP is enabled as per this post https://community.bt.com/t5/BT-Fibre-broadband/ASUS-DSL-AC68U-CORRECT-SETTINGS/td-p/1839925 

DSL modulation **** VDSL2
ANNEX Mode **** ANNEX B
Dynamic Line Adjustment (DLA) ENABLED
SRA (Seamless Rate Adaptation) ENABLED
G.INP (G.998.4) ENABLED

ADSL Settings

Stability Adjustment DISABLED
Rx AGC GAIN Adjustment STABLE
ESNP - STABLE
Bitswap ENABLED


VDSL Settings

VDSL Profile 30a MULTI MODE
Stability Adjustment DISABLED
Current SNR Margin: 6.2 dB
Rx AGC GAIN Adjustment STABLE
UPBO - Upstream Power Back Off. OFF
ESNP - Enhanced SNP. STABLE
Bitswap ENABLED
G.vector (G.993.5) ENABLED
Non-standard G.vector (G.993.5)ENABLED

[#9]

Hi flanzm,

Up until Openreach last played around with my line my attenuation was lower(approx 16;5), and my sync rates were in the region of 33-42, which they had been for 2 years or more, although my actual speeds had fallen quite dramatically in May/June as I said earlier.  I applied the settings as per the BT community suggestions - but don't try Annex Mode B, it won't reconnect the DSL line. Although all the other settings did reduce my SNR ratio, the actual speed seems locked at c25 mbps. anyway.

Thanks anyway for your suggestions and advice. I'm afraid that since Openreach did their 'repair' I'm stuck with the new, lower speeds, and locked into it by the new contract. What really annoyed me though was the BT engineer who said that because of my line distance from the cabinet there was no way I could ever have got more than 20 mbps, despite me showing him 2 years worth of speed checks!!