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Fibre - 12 months experience - does it slow down?

bugs4me
Grafter
Posts: 41
Registered: 21-06-2015

Fibre - 12 months experience - does it slow down?

Started fibre 12 months ago. Line attenuation is 33.8 and the SNR has always been around the 7 mark.

Download speed was in the 10Kbps range when it was first installed. Since then the download speed has gradually deteriorated and is now in the 6.5 range. Rebooting the router doesn't help.

Is this normal as more folks get connected from the cabinet or is there something else?

My line stats from the Billion router -

Line Coding (Trellis) On On
SNR Margin (dB) 7.8 6.3
Attenuation (dB) 33.8 0.0
Output Power (dBm) 8.7 10.5
Attainable Rate (Kbps) 7731 1129
 
Rate (Kbps) 6619 1129
 
B (# of bytes in Mux Data Frame) 195 31
M (# of Mux Data Frames in an RS codeword) 1 1
T (# of Mux Data Frames in an OH sub-frame) 0 52
R (# of redundancy bytes in the RS codeword) 16 0
S (# of data symbols over which the RS code word spans) 0.9391 0.8858
L (# of bits transmitted in each data symbol) 1806 289
D (interleaver depth) 4 1
I (interleaver block size in bytes) 212 32
N (RS codeword size) 212 32
Delay (msec) 0 0
INP (DMT symbol) 41.00 0.00
11 REPLIES
Plusnet Help Team
Plusnet Help Team
Posts: 5,435
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Registered: 01-01-2012

Re: Fibre - 12 months experience - does it slow down?

It could be down to Crosstalk but the only person who can confirm that would be a Openreach engineer.

The estimated distance from your cabinet to your property is 2.1km so it's not likely to improve any time soon I'm afraid.

If this post resolved your issue please click the 'This fixed my problem' button
 Matthew Wheeler
 Plusnet Help Team
bugs4me
Grafter
Posts: 41
Registered: 21-06-2015

Re: Fibre - 12 months experience - does it slow down?

Thanks for the response Matthew. So it looks like it's all going to be downhill from here as more folks take up fibre. If the uptake continues then I'll probably be back to pre-fibre speeds in 12 months.

Cannot see any point in getting Openreach involved as I doubt if they would be willing (or able) to do anything.

Such is life and again thanks for replying.

nblackburn
Dabbler
Posts: 24
Registered: 08-07-2009

Re: Fibre - 12 months experience - does it slow down?

I also upgraded to fibre 12 months ago and I've seen a gradual reduction in sync speed from around 28 to 22. I was previously in the clean range but now I'm well into the impacted range.

Bizarrely my highest achievable speed reported by the BT Broadband Availability checker has steadily increased over the last 12 months, while my actual speed has reduced Crazy2

So I'll be going back to standard ADSL when my contract is up.

Plusnet Help Team
Plusnet Help Team
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Re: Fibre - 12 months experience - does it slow down?


bugs4me wrote:

Cannot see any point in getting Openreach involved as I doubt if they would be willing (or able) to do anything.


It's definitely worth trying to proceed with a fault for further investigation. One that I raised a week or two ago was fixed off the back of an engineer visit.

If this post resolved your issue please click the 'This fixed my problem' button
 Harry Beesley
 Plusnet Help Team
bugs4me
Grafter
Posts: 41
Registered: 21-06-2015

Re: Fibre - 12 months experience - does it slow down?

It is frustrating to see the speed gradually drop. My exchange is still on ADSL even thought 21CN was planned many blue moons ago.

So the big fanfair from BDUK and Openreach having taken the money probably will result in going back to where we started. Hope I'm wrong but unless you're lucky to be in a cable area then that's how it's looking - well in my case anyway.

Some folks that I know, on the same exchange as myself, are not going to have their cabinet fibre enabled as there's a stream/brook or two in the way and that involves the Environment Agency. So they are being offered satellite - hardly suitable unless you are a light user.

Andrue
Pro
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Registered: 12-01-2015

Re: Fibre - 12 months experience - does it slow down?


bugs4me wrote:

So the big fanfair from BDUK and Openreach having taken the money probably will result in going back to where we started. Hope I'm wrong but unless you're lucky to be in a cable area then that's how it's looking - well in my case anyway.


To be fair everyone involved in the technical side of rolling out FTTC has always known about crosstalk. It was probably one of the biggest concerns around the technology. A feature called 'vectoring' was developed to mitigate the effects but so far BT are unwilling to make widespread use of it. The problem is that it came just a bit too late and I think BT have decided to spend the money on the next generation of DSL (G.FAST) instead. They have indicated they might use vectoring in some BDUK areas to help increase cabinet footprints but they've been a bit vague about it.

I think on balance this is the right approach. The next generation of DSL (called G.FAST) comes with vectoring as standard so I think it's better for BT to push ahead with that rather than spending money bolstering up technology that is already slated for replacement.

It's also worth noting that a gradual slide in performance isn't certain. Vectoring isn't just about the number of customers on a cabinet it's about which cables are in use and how close they are to each other. The impact of crosstalk therefore depends on luck. A heavily used cabinet increases the chances of crosstalk impact but doesn't guarantee it. You might have had all the crosstalk impact you're going to get. Or of course you might be about to get a bucket full just because one more customer signs up.

Terranova667
Pro
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Re: Fibre - 12 months experience - does it slow down?


bugs4me wrote:

Thanks for the response Matthew. So it looks like it's all going to be downhill from here as more folks take up fibre. If the uptake continues then I'll probably be back to pre-fibre speeds in 12 months.

Cannot see any point in getting Openreach involved as I doubt if they would be willing (or able) to do anything.

Such is life and again thanks for replying.


Don't assume everything is down to crosstalk or that Openreach won't do anything, When i first had fibre installed i had 65Mb down and 10Mb up and over time that had dropped to my current 48Mb down 3Mb up, I assumed the loss at least on the down side of things was mostly due to crosstalk but it turns out that it may actually be down to my current fault which a Openreach engineer discovered to be a D-side line issue from the DP ( drop point) to the Fibre cab.

Point is only a Engineer can know for sure what the cause of your speed loss is, If your under the Estimate for the line there is no harm in getting it looked at, If it's crosstalk then at least you know if it's a fault then you have every chance of it being fixed and your speed returning. 

 

bugs4me
Grafter
Posts: 41
Registered: 21-06-2015

Re: Fibre - 12 months experience - does it slow down?

Thanks everyone for the feedback. I did an on-line chat with PN and they reset a few things. No difference. I recall though that both Openreach and Western Power were working on or very close to the cabinet a week or so ago - both at the same time. May be unrelated and just a coincidence.

I've raised a ticket with PN and will report back in due course

wisty
Pro
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Registered: 30-07-2007

Re: Fibre - 12 months experience - does it slow down?

I've had FTTC ( a BDUK Project) since last October. When I started the downstream SNR fluctuated between 10.0 and 10.3. It has gradually reduced over time to its current 9.0 - 9.3.

 

This has not affected my speeds as I am on a 40/2 product, and the speed is still solid at 40, but it has ben interesting to see the way it has dropped in steps presumably as more people in the village have switched to Fibre from ADSL.

Gigaclear are currently digging their FTTP product towards the village. One or two people a long way from the cabinet are already committing to go with them. It will be interesting to see what they offer in a year's time when my contract is up.

bugs4me
Grafter
Posts: 41
Registered: 21-06-2015

Re: Fibre - 12 months experience - does it slow down?

It's also interesting how different routers perform on the same piece of antiquated copper wiring in my neck of the woods. Using the supplied PN modem with the OR box which was originally installed - the speed was 50% of what was expected. Going to a Billion and cutting out the OR box and the speed jumped to 10Kbps.

When the speed recently dropped I hooked back up the old PN and OR 'system' and the speed was 3.5Kbps - not much higher than when I was on the old ADSL arrangement. Seems as though the Billion Broadcom chip is more preferable in my part of the world. Hmmm.......

 

bugs4me
Grafter
Posts: 41
Registered: 21-06-2015

Re: Fibre - 12 months experience - does it slow down?

Reporting back as promised. Fault ticket opened and the response was refreshingly prompt.

Today PN stated no fault found and requested a BTW speedcheck. Hey presto, everything has returned to normal.

So whilst PN (apparently) did not get involved then I don't believe in a coincidence. So my thanks to them for quietly sorting (in the background) and also the prompt service.

Praise where praise is due.