Acceptable Range of Speeds.Have the always been so wide?

[#1]

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Your estimated line speed If we've done a line check for you, we provide an estimate of the broadband speed that your line should support. Please see above for the 'Estimate line speed'. We have also included a speed range, as the speed of your service can vary due to the nature of broadband.

Wouldn't it be so much better of you could view your connection and instead of being presented with a virtually meaningless "estimated line speed" you could see what your Fault Threshold Rate actually is? 

[#2]

It would be even better if we knew how they calculated "estinated line speed" as in my case it bears no relationship to reality
From the Plusnet page

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Estimated line speed: 1.5Mbps (Accurate to within +/- 1Mbit) - Checked on 2012-09-13 11:07:31

From the BT Wholesale checker using the telephone number

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Our test also indicates that your line currently supports an estimated ADSL Max broadband line speed of 1.5Mbps; typically the line speed would range between 1Mbps and 2.5Mbps. Our test also indicates that your line currently supports an estimated ADSL2+ broadband line speed of 2Mbps; typically the line speed would range between 1Mbps and 3.5Mbps.

and from the BT wholesale checker using the post code

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Our check also indicates that your line currently supports an estimated ADSL Max broadband line speed of 1.5Mbps; typically the line speed would range between 1Mbps and 3.5Mbps Our check also indicates that your line currently supports an estimated ADSL2+ broadband line speed of 2Mbps; typically the line speed would range between 1.5Mbps and 4Mbps.

and from the BT wholesale checker using my address

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Our check also indicates that your line currently supports an estimated ADSL Max broadband line speed of 2Mbps; typically the line speed would range between 1Mbps and 3.5Mbps. Our check also indicates that your line currently supports an estimated ADSL2+ broadband line speed of 2.5Mbps; typically the line speed would range between 1Mbps and 4Mbps. .

To summarise
Plusnet 1.5Mbps Range 0.5 - 2.5Mbps
For 21CN
BTw (phone number) 2Mbps Range 1.0 - 3.5Mbps
BTw (post code) 2Mbps Range 1.5 - 4.0Mbps
Btw (address) 2.5Mbps Range 1.0 - 4.0Mbps
Actual sync is in the range 4.5 to 5.0Mbps
For 20CN
BTw (phone number) 1.5Mbps Range 1.0 - 2.5Mbps
BTw (post code) 1.5Mbps Range 1.0 - 3.5Mbps
Btw (address) 2.0Mbps Range 1.0 - 3.5Mbps
Actual sync is in the range 4.5 to 5.0Mbps

[#3]

Quote from: Oldjim

Doing a bit of digging I found this https://www.btwholesale.com/shared/document/Application/Orders_and_Faults/Best_Practice_Guides/Fault... updated 2007 but is for ADSLMax not 21CN Quote Should be used on a Broadband Max circuit when the line speed (downstream line rate) drops at least 30% below the stated (pre determined) minimum acceptable level (maximum stable rate). This is known as the fault threshold rate.   For 21CN this http://support.zen.co.uk/kb/KnowledgebaseArticle.aspx?ArticleID=10537 states Quote Fault Threshold Rate:  The fault threshold rate (or FTR) is 80% of the MSR.  If the line rate drops below the FTR for more than 8 hours in a week period it is considered a fault and a low threshold breach fault can be raised. So it looks as though the fault threshold rate calculation changed between 20CN and 21CN

Thanks for those links, Jim.
I can't see, though, that the Zen article refers specifically to 21CN.
When I referred earlier to my own experience of it being always 80%, that was on ADSL1 on 20CN. I haven't checked it since recently moving to ADSL2+ on 21CN.

[#4]

It does if you look at the speed they give as an example - it is too high for 20CN

[#5]

The sad thing is that we are arguing about this.  Maybe we should all call Plusnet on Monday and ask them to tell us what our MSR and FTR are; then we'll know for sure?  

[#6]

That could be interesting
In my case is it the value when I was on 1Mb fixed, ADSLMax (20CN), ADSL1 (21CN), ADSL2 (21CN) or ADSL1 (21CN)
You can see I have been messing about a bit

[#7]

Quote from: Oldjim

It does if you look at the speed they give as an example - it is too high for 20CN

It just suggests to me that the same percentage applies to all modes - can't see why it should be any different.

Quote from: ReedRichards

The sad thing is that we are arguing about this.

Nay, just trying to establish the facts. 

Quote from: ReedRichards

Maybe we should all call Plusnet on Monday and ask them to tell us what our MSR and MTR are; then we'll know for sure?

Good idea! Will report back.
Maybe this discussion should be split off?

[#8]

Here is my MSR / FTR
MSR - 11360 / FTR - 9088, this equates to 80%
My line rate was 8.9 for around 5 days, so if I am correct this should qualify me for a low threshold breach fault. ?

[#9]

Quote from: ReedRichards

Maybe we should all call Plusnet on Monday and ask them to tell us what our MSR and MTR are; then we'll know for sure?

Just phoned in and obtained figures of MSR 3424 and FTR 2739. So, 80% on 21CN, as it was on 20CN.
As noted earlier, I believe there was a time, up to around 2007, when it was 70%.

[#10]

@JamesM
If your speeds are below your threshold which is 9088kbp/s then yes you have a fault threshold breach.
Having checked your line it is currently above that and the majority of the time it is above it(apart from the time you stated.)
If it does go under this then we can raise a fault with our suppliers for this, so if you notice that it is under your threshold then let us know.

[#11]

My figures:
MSR:  8128
FTR:  6502
So it is 80% on 21CN.
For some reason, during the training period my sync rate dropped and dropped.  It's been fine ever since but the MSR/FTR values are disappointingly low.  Perhaps i should demand a recount?   

[#12]

That really looks as though the MSR was set before you went on to 21CN as that is the maximum speed on ADSL1 or 20CN
Does that make any sense - do you remember what your sync rate was before going onto ADSL2+

[#13]

No, Jim, my line was never that good on ADSL1; it's just a coincidence.  I have about 38dB of attenuation.