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Author Topic: Marginal VDSL installations  (Read 3354 times)

waltergmw

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Marginal VDSL installations
« on: October 04, 2012, 12:54:38 PM »


@ Kitz,

Here's a short summary for Kitz & any who can shed any more light on the quagmire !

BT Wholesale web site will always provide a VDSL speed estimate on all lines connected via their exchange equipment. N.B. This excludes full LLU providers such as TalkTalk**, but BT then estimate using a postcode. All CPs have estimators too but for many low estimate services they just refuse to offer a service. ** Conversley BT Wholesale will estimate for O2 or Be, I believe, because they don't use their own LLU phone service.

The BT Wholesale estimator rejects all very poor services by saying 100 KiloBits per sec up & down. I know of long stretches of lousy cable where nobody can achieve anything, yet some have ADSL 2 services running around 2 Mbps.

The grey, if not totally foggy, area is what the lowest estimator figures that a CP will attempt to offer a service, usually with no speed guarantee at all. Some seem to use the 12 Mbps figure, whilst others will attempt right down to 5 Mbps.

Come the installation day, the BT Openreach engineer will not proceed if his test equipment detects a line fault which the client often has to organise a repair visit by a different Openreach engineer. The VDSL appointment has then to be rescheduled via the CP.

If the line testis O.K. then BT Openreach will attempt the installation PROVIDED the speed at the house exceeds a minimum which might be the 12 Mbps figure if a strict interpretation of the rules is being followed. However if the sun is shining & copious quantities of tea & bacon butties, tea cakes etc. are available, most engineers seem content to complete a minimum speed installation of 5 Mbps.

Perhaps BS & others might please comment / confirm my understandings ?

Kind regards,
Walter
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kitz

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Re: Marginal VDSL installations
« Reply #1 on: October 04, 2012, 03:15:53 PM »

This is only partial information as I dont know about FTTC, but Im just including some information that I know of with regard to the checker for adsl2+

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My understanding is that theres several resources that BT use.

History and current information obtained from that phone number.
Average data in the surrounding area.

I was told at one point that the early speed estimates were based on line length, but this was back in the days when BT held such data on practically all lines (except KCC).  I have never been able to confirm whether this is true or not so do not take this as gospel.

----

If the line is BTw based then they will have an idea of what the line is capable of so in theory if they apply their FTTC calculation on the distance from the cab,  then it should be fairly close, although with usual BT conservativeness.

If the line is FMPF (ie Sky or TT), BT will have no data of that phone number. For adsl2+ the database will call upon an average of information that it does have from the surrounding postal code area.
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Black Sheep

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Re: Marginal VDSL installations
« Reply #2 on: October 05, 2012, 06:18:59 PM »


@ Kitz,

Here's a short summary for Kitz & any who can shed any more light on the quagmire !

BT Wholesale web site will always provide a VDSL speed estimate on all lines connected via their exchange equipment. N.B. This excludes full LLU providers such as TalkTalk**, but BT then estimate using a postcode. All CPs have estimators too but for many low estimate services they just refuse to offer a service. ** Conversley BT Wholesale will estimate for O2 or Be, I believe, because they don't use their own LLU phone service.

The BT Wholesale estimator rejects all very poor services by saying 100 KiloBits per sec up & down. I know of long stretches of lousy cable where nobody can achieve anything, yet some have ADSL 2 services running around 2 Mbps.

The grey, if not totally foggy, area is what the lowest estimator figures that a CP will attempt to offer a service, usually with no speed guarantee at all. Some seem to use the 12 Mbps figure, whilst others will attempt right down to 5 Mbps.

Come the installation day, the BT Openreach engineer will not proceed if his test equipment detects a line fault which the client often has to organise a repair visit by a different Openreach engineer. The VDSL appointment has then to be rescheduled via the CP.

If the line testis O.K. then BT Openreach will attempt the installation PROVIDED the speed at the house exceeds a minimum which might be the 12 Mbps figure if a strict interpretation of the rules is being followed. However if the sun is shining & copious quantities of tea & bacon butties, tea cakes etc. are available, most engineers seem content to complete a minimum speed installation of 5 Mbps.

Perhaps BS & others might please comment / confirm my understandings ?

Kind regards,
Walter

Hmmm ?? Not 100% certain myself about the scenario where the line tests faulty upon the engineering visit, ergo the FTTC install is put on hold ??

That may be the case for the ex-M.O.D. guys and MA's (Modern Apprentices), But as a multi-skilled engineer myself (like many others), I feel I may be expected to fault the circuit as part of the job ?? Its a good point, and one I shall endeavour to find the answer to.

I can answer your last point though ...... there is NO lower limit to FTTC products anymore. It used to be sub-15Mbps, but finally common-sense prevailed and the ISPs (probably under pressure from EU's) have relented and agreed that if the EU is happy with, lets say, 2Mbps on FTTC, then it stays. This is an extreme example, but we do get them, and the EU is happy to get 2Mbps from their previous speed of 256Kbps.
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waltergmw

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Re: Marginal VDSL installations
« Reply #3 on: October 06, 2012, 10:10:38 PM »

@BS,

Thanks very much; that is most helpful.

The other controlling factor that remains is the policy of the ISP.
When using the broadband checker - I.e. no human involvement, I note that some still seem to put a lower limit and usually come up with a statement such as "Fibre broadband is not yet available in your area, but please register you're interest ...."
Perhaps the cost of an extended "discussion" with BT O would empty their piggy bank ?

I believe Zen Internet have a 5 Mbps limit so won't offer any service, even without any guarantee below that. I have yet to discover what happens if the actual achieved sync speed varies wildly from the estimate.

Kind regards,
Walter
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Dazzieb

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Re: Marginal VDSL installations
« Reply #4 on: October 30, 2012, 11:20:28 AM »

This is only partial information as I dont know about FTTC, but Im just including some information that I know of with regard to the checker for adsl2+

----

If the line is BTw based then they will have an idea of what the line is capable of so in theory if they apply their FTTC calculation on the distance from the cab,  then it should be fairly close, although with usual BT conservativeness.


I would have normally agreed with you there but I have serious doubts. Back in April I did a check, you may see my previous posts that relate to this, the BTw checker advised that I could receive 17.9 down and 1 up, but when the BT Engineer arrived to complete the install he could only get 2.5 down, this is wildly out and I refused the service owing to the relatively high speed I currently receive on my ADSL (MAX) product. The engineer stated that it may be owing to a stretch of Aluminium on the line or the fact that I am 1.6 miles from the FTTC (Cab), the latter being the most likely but wouldn't the BTw checker be able to establish this?

Funnily enough I received a call from BT about a month ago and they tried to sell me the product again (after I subsequently asked to be removed from their database until they could supply me with a suitable service). I advised them of their previous visit but the BT representative advised that they know about that, apologised and said that all had now been sorted and I could get the service. When using the BTw checker I still see the same reported speeds and no change whatsoever. I have relluctantly re-ordered and have an engineer attending my property next Friday. I am under no illusion that things have actually changed, so only 2 things can happen:

1) I do get the advertised speed or 1 either side, which I will be stunned at.
2) I get turned down again and I will rip through BT Customer Services (my last communication on the previous matter was with the head of BT Openreach and BT Customer Services).

I will wait to see what happens...

Apologies to the OP for jumping in on this thread with my issues...
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Black Sheep

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Re: Marginal VDSL installations
« Reply #5 on: October 30, 2012, 11:55:50 AM »

SP/ISP's are a wonderous bunch. The yarns that spout forth, in order to 'seal a deal' are incredible at times !!

Only last week, I was on an  ADSL provide to a farm that was 7.14Km (76dB attenuation) worth of cable away from the Exchange. I didn't check for certain, but would hazard a guess at the PCP to be approx 2Km from the EU ?? I was passing this info on to the EU during the course of my work, explaining that he'd be lucky to get ADSL, etc etc ........ if he did, it would be slow'ish etc etc .................

Anyhows, whilst still on-site, after rehashing the 'pre-wired' builders mess of wiring and running an error-check on his now 0.4Meg circuit, the same ISP (SKY) rang the EU.

They basically asked if the EU wanted to migrate to FTTC ?? I could hear the EU explaining he was a long way from the PCP but they were insistent he could get service. To say he was flabberghasted when I explained to him that the Exchange he is fed off hasn't got FTTC, and isn't even pencilled in to have it until the end of 2013, is an understatement !!!  :no:

He reiterated to me that the SKY caller had said he could get it now if he signed up ?? Madness. 
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