+/- 1 megabit?

[#1]

There is a fairly common theme among a few posts on here - that is the reference to +/- 1 megabit.  The whole point of the error bars is that that is the region within which your connection should be, unless it is further qualified (something like "95% of customer's will receive x +/- 1megabit") .  I'm sure you could share the amount of customer's who are achieving their estimate or better expressed as a percentage?
I'm surprised Plusnet quote to this level of accuracy - less than a 2% margin for a full rate connection - and is the kind of numerical abuse you see all the time.  It is even stranger when you consider this in the context that almost any DLM event is going to drop you by WAY more than 1megabit/sec.
Why not just change the wording on the +/- 1 megabit, as it is surely an unreasonably tight specification?  It just seems to be setting yourselves up for failure really...!

[#2]

We don't quote this anymore, it was a problem especially on the Fibre signups.
I've attached a screenshot of the new estimates for Fibre.

[#3]

i think it is still shown in the member's centre though - so that should probably be nuked too?
"Estimated line speed:
75Mb (Accurate to within +/- 1Mbit) - Checked on 2013-03-25 01:27:48"
Anyhow, good to see it isn't shown to new signups anymore.

[#4]

As an entertaining aside, BT Retail don't even quote the figure as an estimate!  They do for ADSL but not for fibre.  Go figure!

[#5]

This is going to change in the near future, we've made a few amendments to this, but it will require a new line check to be performed to update the details to remove the +- 1Mb/s which we're currently working out how best to do.

[#6]

Problem is with any ISP using the BT Wholesale checker data for speed estimates is that is often inaccurate ,only recently BT have changed some of the speed estimates mostly to lower values, My line have always had an estimate that is inaccurate, more so with FTTC , fortunately for me my speeds are a lot higher , and if an isp,or BT openreach  starts to rely upon  BT 's speed estimates to to avoid acknowledging,diagnosing or reporting  faults where something causes a big decrease in speeds  it will be a sad day for the consumer

[#7]

I'm not sure I totally agree.  FTTC for reasons of near and far end crosstalk will (for many customers) see a natural fall in performance as cabinets fill up and as more lines running in the same duct are activated for FTTC.  So a line needs to be drawn in the sand somewhere - I think it is reasonable in many cases on FTTC that if the user was lucky enough to get a faster speed due to the cabinet being empty, and then dropping to the original speed estimate, that that can be considered to not be faulty. 
I would imagine that to start with Openreach use a mathematical model, and then as the cabinet starts to fill up perhaps they fill in the model with actual results from lines (as there are always bound to be local factors such as aluminium, cable routes, etc).  Or perhaps the overall model has changed now based on field data from more sites.
It would of course be nice to be able to see information about cabinet usage when the wholesale checker / speed tester runs, so that you can understand what has happened.  You'd imagine that eventually most cabinets will be pretty much full, but it would help explain to people why the speed they are seeing might not last.
My original point (and I guess why plusnet have / are making the changes that they are) is that once you have an understanding of the technology you realise that there is no-way you could ever confidently provide estimates +/- 1megabit.  Of course, the branding of FTTC as "fibre" products doesn't help, as you wouldn't expect a "fibre" service to degrade in this way.  In fact, I'm a bit surprised that the ASA or similar haven't got involved over this branding as for quite a few people "fibre" can mean a kilometer of copper / aluminium if you are really unlucky.  My ADSL service was "fibre" from the exchange!

[#8]

They should be replacing all those under performing D'side pairs ideally with FTTP There is talk of vectoring ,but how well it will work (when rolled out) is anyone's guess really,
BT 's estimates are based on assumptions , and as every line is in some-way different .
those assumptions can be absolutely meaningless  ,They are estimates and should never become more than that. or relied upon
I would bet that there are a lot of FTTC cabs in some areas  that have very few connected to them, even 12mths  after  accepting orders

[#9]

There is no fibre in our area so this is all for future information.
Are you saying that if in the future, I think I want to have fibre, then I am expected to sign up to a contract for 18months based on a cost that Plusnet guarantee to take precisely and regularly every month but for a service which they cannot define?
I can live with being given an estimate with an error margin on it but without the tolerance figure how bad does it have to get before Plusnet are no longer meeting their committment to deliver me a broadband service.  At 70Mbps,I accept that a tolerance of +/-1 is pretty tight but at the bottom end of the possible range +/-1 is nothing remarkable without Plusnet now deciding it cannot even guarantee that.
And if I understand the previous posts correctly, having got fibre initially running at speed X, then it can legitimately and uncorrectably change to speed Y where Y could be X/2 or worse. And Plusnet are still going to go on taking the original amount of money for a service in this case only half as good?
Please tell me I have all of this wrong - surely I am not expected to buy an undefined service.

[#10]

Plusnet and I think every other ordinary residential ISP are not going to guarantee you get any particular speed. Does 70Mbps falling to 50Mbps make much actual difference, besides for speedtest scores? It might matter more for the people whose FTTC speeds are closer to 30 or 20 Mbps, but then those people have to pay the same as those getting 77Mbps anyway.

[#11]

Dredging my memory, I believe that Plusnet (or Openreach in reality I suppose) will not consider a fiber system adequately installed until it achieves at least 20Mbps. Can anybody confirm whether my memory is working and also whether that 20Mbps is a minimum initial speed that can subsequently drop to a lower speed without correction or is it a long term guaranteed minimum that will get all the troops leaping if it is breeched.
I accept that 50Mbps is not very different to 70Mbps in real life terms but an estimate either has some meaning or not. If it has meaning then it should have a tolerance or a confidence interval on it and the customer should be able to rely on that figure. If the figure is so meaningless that Plusnet/Openreach have no confidence in it then they should not be using it in their sales material. Doing so takes us into Quack Doctor territory and in my opinion, false advertising.
That tolerance would normally be a percentage of the estimate rather than an absolute figure. That is more true to real life and real engineering and obviously could be equivalent to 20Mbps at 70Mbps and 6Mbps (roughly) at 20Mbps though 14Mbps versus 20Mbps is certainly more disappointing than 50 versus 70.
If I buy a pint of milk, I do not mind a BOGOF offer that nets me two pints but I do object to finding I only get half a pint. Why should the internet be different? When I commit my money to Plusnet, what do Plusnet commit to me?

[#12]

Quote from: EnglishMohican

There is no fibre in our area so this is all for future information. Are you saying that if in the future, I think I want to have fibre, then I am expected to sign up to a contract for 18months based on a cost that Plusnet guarantee to take precisely and regularly every month but for a service which they cannot define? I can live with being given an estimate with an error margin on it but without the tolerance figure how bad does it have to get before Plusnet are no longer meeting their committment to deliver me a broadband service.  At 70Mbps,I accept that a tolerance of +/-1 is pretty tight but at the bottom end of the possible range +/-1 is nothing remarkable without Plusnet now deciding it cannot even guarantee that. And if I understand the previous posts correctly, having got fibre initially running at speed X, then it can legitimately and uncorrectably change to speed Y where Y could be X/2 or worse. And Plusnet are still going to go on taking the original amount of money for a service in this case only half as good? Please tell me I have all of this wrong - surely I am not expected to buy an undefined service.

That's basically how it is, as Xdsl is rate adaptive, they Openreach will not give any guarantees and they never have , infact  the twisted pair copper local loop was never designed with broadband in mind,hence the lack of any kind of guarantee's the most you get out of them is their SIN specs , unless you get into the realms of leased lines or FTTP , My main gripe is the fact that the BT openreach/wholesale speed estimate for my line is and always has been inaccurate by a significant amount, lower , and that they base the first FTTC estimate on assumptions alone, as they are often given before the cab is accepting orders

[#13]

Quote from: EnglishMohican

If I buy a pint of milk, I do not mind a BOGOF offer that nets me two pints but I do object to finding I only get half a pint. Why should the internet be different? When I commit my money to Plusnet, what do Plusnet commit to me?

There is a significant difference between pouring the same amount of milk into a milk carton each time and ensuring that you are getting speeds to an estimate through multiple miles of connectivity equipment.  You are comparing apples and oranges.
If you want to have an assured rate, you need a different product, perhaps a leased line of some sort.  They are though, much more expensive.  So, if you don't want to pay that much, you can settle for an product based on a technology which will run to an estimate but will be affected be a lot of different things.

[#14]

Quote from: Kelly

You are comparing apples and oranges.

I would be paying with pounds for both.

Quote from: Kelly

There is a significant difference between pouring the same amount of milk into a milk carton each time and ensuring that you are getting speeds to an estimate through multiple miles of connectivity equipment.

Three thoughts - FIrst thought - perhaps if you had spent time designing the kit that fills thousands of cartons with a precise amount of milk an hour without splashing it all over the place you would not be so dissmissive.
Second thought. As I am sure you do know, electronics and communication technology is a science. If you know the properties of the wires and their lengths you can perform remarkably good calculations as to how they will perform. The problem seems to be that the Openreach database is full of errors - on my own line they offer an estimate on basic ADSL that is way in excess of anything that is ever going to be possible. An Openreach engineer explained that probably the database used to calculate the estimate contained the wrong data - that my line length was for my previous house or whatever. That is not professional, competent, statistical estimating - it is not even guesswork.
Third thought - you have not answered the question in my previous post - does Plusnet/Openreach guarantee any level of performance  irrespective of the estimate. If so - is it 20Mbps?

[#15]

How would a 20Mbps minimum guaranteed speed work in practice? What would happen if your FTTC estimate is "up to 21.8", but when the engineer installs it, they only achieve 19.5? After much fiddling around, replacing the master socket a couple of times, trying different ports in the FTTC cabinet, they can't manage to increase the speed to over 20. Would they then:

• Undo the FTTC installation, restore the ADSL service, and say sorry you can't have FTTC, it turns out you're just too far from the cabinet, you'll have to stick with your 3Mbps ADSL?


• Knock some amount off the price?


• Install FTTPoD for free?


• Return later to replace the entire copper cable between your house and the cabinet?