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Standard User billford
(elder) Thu 08-Aug-13 14:13:19
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FTTC speeds


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My BQMs showed a brief disconnection last night in the wee small hours (confirmed by the router log), nothing of note. Until I looked more closely and saw my latency had dropped a bit... so off to the BT speedtester which showed a profile of 70.8Mbps.

The BT estimate for my number is "up to 54.8Mbps". A bit of conservatism is fine, but that's ridiculous!

More to the point, 70.8Mbps is the highest it's ever been; even when I first went to 80/20 about 18 months ago it was only about 68-69Mbps (as far as I can remember), and it was down in the low 60's for a while (around 8 months ago). I find it hard to believe that the number of users on my cabinet has dropped since then... could BT be doing some unpublicised field trials of vectoring, and could this explain the above?

(The modem is a bog-standard HG612, one of the early ones that were mostly swapped out because of over-heating, but mine escaped)


eta- Or has anyone got a simpler explanation?

Bill
A level playing field is level in both directions._________________Planes and Boats and ... ______________BQMs: IPv4 IPv6

Edited by billford (Thu 08-Aug-13 14:19:22)

Administrator MrSaffron
(staff) Thu 08-Aug-13 14:30:29
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Re: FTTC speeds


[re: billford] [link to this post]
 
Vectoring is about much larger boosts in speed then just 1 to 2% so probably the DLM has simply relented slightly on the line

Could be as simple as a noisy local plasma TV turned off while neighbours are off on holiday for a few weeks

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User billford
(elder) Thu 08-Aug-13 14:37:33
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Re: FTTC speeds


[re: MrSaffron] [link to this post]
 
In reply to a post by MrSaffron:
Vectoring is about much larger boosts in speed then just 1 to 2%
OK, that's a good point
so probably the DLM has simply relented slightly on the line
That would make a pleasant change- it usually dumps me on interleaved if someone sneezes too hard frown

I'll see how it behaves over the coming weeks as the holiday period tails off... I'm about 450m from the cabinet, so quite a few houses to go past!

Bill
A level playing field is level in both directions._________________Planes and Boats and ... ______________BQMs: IPv4 IPv6

Edited by billford (Thu 08-Aug-13 14:41:54)


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Standard User MHC
(sensei) Thu 08-Aug-13 14:41:34
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Re: FTTC speeds


[re: billford] [link to this post]
 
Would vectoring change latency? Probably not, or if anything it might increase it marginally.

The drop could be a reboot or upgrade at a node somewhere in the network and if one node in the path is removed a small decrease could occur. Your speed, might have been sitting there waiting to improve slightly for a few days ...


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M H C


taurus excreta cerebrum vincit
Standard User billford
(elder) Thu 08-Aug-13 14:49:58
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Re: FTTC speeds


[re: MHC] [link to this post]
 
In reply to a post by MHC:
Would vectoring change latency?
I've no idea crazy
The drop could be a reboot or upgrade at a node somewhere in the network and if one node in the path is removed a small decrease could occur.
Could have been... but it looked more like a (DSLAM initiated) re-sync was involved rather than a PPP drop due to re-routing. Can't be sure because I was pounding my ear at the time.

Bill
A level playing field is level in both directions._________________Planes and Boats and ... ______________BQMs: IPv4 IPv6

Edited by billford (Thu 08-Aug-13 14:53:14)

Standard User MHC
(sensei) Thu 08-Aug-13 15:09:23
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Re: FTTC speeds


[re: billford] [link to this post]
 
In reply to a post by billford:
In reply to a post by MHC:
Would vectoring change latency?
I've no idea crazy


I would guess it might increase it.

Simplistically, every line in the cabinet need to be sampled, that data processed and the individual calculated inverse signal for each line injected. That will take a finite time, so for it to work properly the actual modulated data stream would also need to be delayed to align with the forecast.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
Standard User billford
(elder) Thu 08-Aug-13 15:21:10
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Re: FTTC speeds


[re: MHC] [link to this post]
 
In reply to a post by MHC:
Simplistically, every line in the cabinet need to be sampled, that data processed and the individual calculated inverse signal for each line injected. That will take a finite time, so for it to work properly the actual modulated data stream would also need to be delayed to align with the forecast.
That's true, but it's essentially an analog signal system- one advantage of analog over digital is that it doesn't calculate, it just behaves as dictated by the component values so, in some applications, it can be faster.

But as all I know about vectoring is how to spell it, that's all purely hypothetical smile

Bill
A level playing field is level in both directions._________________Planes and Boats and ... ______________BQMs: IPv4 IPv6
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