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Standard User WWWombat
(experienced) Sun 16-Dec-12 01:05:28
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Re: Affect of distance on fibre line


[re: MrSaffron] [link to this post]
 
Yes. I hear it's proving to be a problem in Germany.
Standard User Ignitionnet
(knowledge is power) Sun 16-Dec-12 01:16:03
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Re: Affect of distance on fibre line


[re: MrSaffron] [link to this post]
 
In reply to a post by MrSaffron:
You mean they have read SINET like anyone can?


Does SINET have that level of granularity?

Only thing I could find was the below:

http://www1.btwebworld.com/sinet/498v4p2.pdf

2.2 User Network Interface - General

2.2.1 Dynamic Line Management

Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly
manages lines to maintain a target link quality (speed and stability). It does this for as
long as the product exists.

At provision, the line is put on “wide open” VDSL2 line profiles allowing the
upstream and downstream line speeds to run at the upper limit of the product option
selected.

On the first day of operation, DLM will intervene if severe instability is detected.
Otherwise, DLM will wait until the day after provision before deciding if it must
intervene, provided that the line has been trained up for at least 15 minutes during the
preceding day.

If DLM intervenes it will set a profile with a maximum rate and a minimum rate,
where the minimum rate is set at approximately half of the maximum rate. The
purpose of the minimum rate is to ensure that the line does not train at a rate which is
significantly below the level the line should be able to achieve. If this happened, then
the line is likely to remain at a very low rate until a re-train is forced by the user by
powering off the modem.

Note : It is the DLM system that sets the line profile, and this should not be interfered
with by CPs/users setting rates, SNR margins etc. at the modem.

Note : The upstream throughput is also constrained on the DSLAM to the upstream
rate requested in the order, i.e. 2Mbit/s, 10Mbit/s or 20Mbit/s, so even if the VDSL2
upstream line speed is higher, the upstream throughput is constrained to the level
ordered for the product.
Standard User Andrue
(knowledge is power) Sun 16-Dec-12 10:25:29
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Re: Affect of distance on fibre line


[re: billford] [link to this post]
 
In reply to a post by billford:
In reply to a post by Andrue:
Actually you can't trust Google Maps for measurement. I happened to keep an eye on my car's display today coming back from the golf range and the distance is slightly more than 0.2 of a mile or 300 metres.
I think I'd place considerably more trust in Google maps than an odometer in any car...
i wouldn't. For one thing the car is less than 12 months old.

For another according to Google Earth:

http://maps.google.co.uk/?ie=UTF8&ll=52.07791,-1.371...

That driving range is 236.7 yds long.

Now there's a possibility (remote) that they use special balls and have shrunk that range.

So here's another at my club:

http://maps.google.co.uk/maps?f=q&source=s_q&hl=en&q...

Google maps reckons that's only 258 yds edge to edge - 243 yds playable. That's played with real balls by people who know what they are doing. It's going to be in excess of 300 yds playable, prolly 400 yds edge to edge.

---
Andrue Cope
Brackley, UK

Just because he could. RIP.

Edited by Andrue (Sun 16-Dec-12 10:34:38)


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Standard User Chrysalis
(eat-sleep-adslguide) Sun 16-Dec-12 10:36:34
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Re: Affect of distance on fibre line


[re: Ignitionnet] [link to this post]
 
yes and interestingly that indicates DLM is more leniant the first day (not more sensitive).

Which makes sense given that on install day the engineer will disconnect it few times on installation without DLM triggering.
Moderator billford
(moderator) Sun 16-Dec-12 10:39:12
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Re: Affect of distance on fibre line


[re: Andrue] [link to this post]
 
In reply to a post by Andrue:
For one thing the car is less than 12 months old.
So?

I'd prefer a measuring system whose accuracy didn't depend on air temperature and pressure, tyre pressure, make/type, and state of tread wear (all affecting the rolling radius), but each to their own.

Bill
[email protected] __________________Planes and Boats and ... __________________BQMs: IPv4 IPv6
The author of the above post is a thinkbroadband moderator but it does not constitute an official statement on behalf of thinkbroadband.
Standard User Chrysalis
(eat-sleep-adslguide) Sun 16-Dec-12 10:40:02
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Re: Affect of distance on fibre line


[re: WWWombat] [link to this post]
 
yes I read the same thing this interferes with sub loop unbundling, I think the arguments in favour are the fact sky, talktalk etc. are not using sub loop unbundling they have instead chose to rent openreach equipment, if all those isp's can be persusaded on the merits of vectoring and agree to it I would hope ofcom can see common sense and not block it.

Also in these SIN documents it suggests the current modems are all currently vectoring compatible so no CPE swap should be required also interestingly it states they SRA compatible as well.
Standard User BatBoy
(legend) Sun 16-Dec-12 10:44:15
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Re: Affect of distance on fibre line


[re: Chrysalis] [link to this post]
 
In reply to a post by Chrysalis:
yes and interestingly that indicates DLM is more leniant the first day (not more sensitive).

Which makes sense given that on install day the engineer will disconnect it few times on installation without DLM triggering.
I don't think the engineer will be disconnecting it a few times TBH
On the first day of operation, DLM will intervene if severe instability is detected.



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Standard User Chrysalis
(eat-sleep-adslguide) Sun 16-Dec-12 11:56:21
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Re: Affect of distance on fibre line


[re: BatBoy] [link to this post]
 
of course he did, I watched him he connects a test device first which syncs up, disconnects it, runs some line tests, recconects it, then connects the modem, then after its connected he then power cycled it.

They dont just show up connect the modem and leave.

This did make me wonder how this doesnt affect DLM and the SIN seems to confirm why, that DLM is more leniant on the first day to allow for install routines and I guess the possibility of the end user moving things around as well.

also if you going to quote quote the full statement.

On the first day of operation, DLM will intervene if severe instability is detected.
Otherwise, DLM will wait until the day after provision before deciding if it must
intervene

Edited by Chrysalis (Sun 16-Dec-12 12:00:13)

Standard User BatBoy
(legend) Sun 16-Dec-12 12:02:58
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Re: Affect of distance on fibre line


[re: Chrysalis] [link to this post]
 
So that's 4 reconnections? I wonder how many cause DLM to regard the line as severely unstable.


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Edited by BatBoy (Sun 16-Dec-12 12:03:55)

Standard User BatBoy
(legend) Sun 16-Dec-12 12:05:43
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Re: Affect of distance on fibre line


[re: Chrysalis] [link to this post]
 
In reply to a post by Chrysalis:
also if you going to quote quote the full statement.

On the first day of operation, DLM will intervene if severe instability is detected.
Otherwise, DLM will wait until the day after provision before deciding if it must
intervene
That's not the full statement. Check the full-stops.


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