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<div class="moz-cite-prefix">I think there are to many unknown's to
apply much of this type of logic to NBN2. The 100M/bit question
will be. <br>
<br>
Where will they put the "node". The most logical place will be to
knock over the pillars (big grey knob looking post) and put the
big green graffiti target in it's place. The Node will then cover
what was formally known as the "distribution area" (DA).<br>
<br>
If that's the case the direct main cable usually 300+ pairs
direct to the exchange will be superseded with the fiber &
node. This higher density cable is where most of the cross talk is
seen usually. It's induced in these cables but the root cause is
usually impedance mismatch further down the loop. With the higher
density cable out of the picture I think the cross talk will be
decreased overall but the root cause will still be there to cause
havoc.<br>
<br>
Warning detail ahead !<br>
<br>
Iam assuming BYO CPE and internal customer premisses cable . So
the mismatches will still be there even if someone had the
foresight to go and remove all the bridged tap's in the joining
posts and pits. Most of these exist in large epoxy filled heads
that is basically just 3 pairs scotch locked together stuck in
what looks like the bottom half of a 2l drink bottle and filled
with Epoxy. Some even have passive L/C (inductors/coils of wire)
components in place that were used to balance the loop back toward
the now non existing mains cable. Records for this stuff is flakey
to non-existent. It has to be found. Burred in the ground in
unknown locations encapsulated in epoxy some in asbestos pits.
Some of these pits have been covered by earth or concrete years
ago. There is little financial case to make all this happen. It's
man power intensive. Time consuming dirty work. It does not fit
the Pizza delivery business model and wont happen. You may as
well put in fiber at that point. <br>
<br>
If i was tasked with this brief. That is to get this thing working
as quickly and cheaply as possible so it can be sold. This is what
I would do. <br>
<br>
Get a contractor to build a custom node housing. It would be a big
box that would allow the dslam/vdsl equipment at one end and the
other end would fit over the existing pillar. Jumpers could then
be run from the dslam to the pillar untill all subscribers were
off the main's cable. The mains cable could then be ripped out by
a disposal contractor to sell the copper. <br>
<br>
Nothing would be done further down the loop. It would work how it
works now best effort. Customer would go to dick smith and get
themselves a vdsl modem with POTS/VOIP port and that would be
that. Average speed would be <25M/bit with a the lucky few
<50M/bit <br>
<br>
It would be very quick to finish. Does not touch the ends of the
CAN where all the problems are and the whole thing could be sold
to a sucker (aka mum&dad's via share offers and super funds)
and we can go through this whole thing again in 10 years.<br>
<br>
Matt.<br>
<br>
<br>
On 13/09/13 10:40 AM, Peter Adkins wrote:<br>
</div>
<blockquote
cite="mid:CAA7vvKkomPFf0nkB8gD8kv+gFR4HomZ3pyzmKQzMJRjns=QA8w@mail.gmail.com"
type="cite">
<div dir="ltr">There's a couple of papers available on the IEEE
around FEXT with regards to ADSL2+ services. More specifically,
how much of an impact cross-talk can have within an environment
where a large number of surrounding pairs in a bundle are also
used to provide an ADSL2+ service.
<div>
<br>
<div><a moz-do-not-send="true"
href="http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4446136">http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4446136</a></div>
<div><br>
From what I understand, FEXT could start to be an issue if a
large number of adjacent xDSL services were deployed with
out the magic of 'vectoring' due to this cross-talk. This
having been said, I could be way off the mark here (I
haven't even had my morning coffee yet!) in which case I'm
happy to be corrected :)<br>
<br>
<br>
</div>
</div>
<div class="gmail_extra">
<div class="gmail_quote">On Fri, Sep 13, 2013 at 8:46 AM, Mike
Trewartha <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:miketrewartha@gmail.com" target="_blank">miketrewartha@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="auto">
<div>With the change in loop lengths, what is the
likelihood of some bodies current decent (ie. 18mbit+)
ADSL2+ sync speeds dropping once FTTN is deployed?<br>
<br>
<br>
Regards, Mike. </div>
<div><br>
Sent from my iPhone</div>
<div class="im">
<div><br>
On 13/09/2013, at 8:32 AM, Paul Brooks <<a
moz-do-not-send="true"
href="mailto:pbrooks-ausnog@layer10.com.au"
target="_blank">pbrooks-ausnog@layer10.com.au</a>>
wrote:<br>
<br>
</div>
</div>
<blockquote type="cite">
<div>
<div class="im">
<div>On 13/09/2013 7:08 AM, Guy Ellis wrote:<br>
</div>
<blockquote type="cite">
<div>Paul,<br>
<br>
In response to your challenge (Exercise for
the reader - work out how VDSL2 would be any
different)...<br>
<br>
In contrast to the current ADSL2+ network,
there are 3 big differences with the proposed
VDSL2 FTTN deployment - <br>
(i) shorter loop lengths (700-800m) <br>
(ii) vectoring (crosstalk--)<br>
(iii) bonding (speed++)<br>
<br>
While such a VDSL2 network is not as good as
fibre, it's no where near as bad as the
current ADSL2+ network.<br>
Right now some poor folks are on 6km loop
lengths, there's plenty of crosstalk and
getting bonding working is a challenge.<br>
</div>
</blockquote>
You can forget about pair bonding in the broader
plan - I sincerely doubt the budget or street
cabinets will be big enough to build two ports for
every dwelling.<br>
<br>
My point was that - without vectoring - the VDSL2
chart would look much the same.<br>
<br>
Sure the axis labels would change - distances to
5km become distances to 800 metres, bandwidth tops
out at 120 Mbps instead of 24 Mbps - but the shape
of the chart would look much the same. A
negligable proportion getting the full 'up to'
speed, roughly 30% of people getting speeds down
to 50% of the "up to" limit, and a large hump
majority of people down the low end getting about
10 - 15 Mbps - probably better than the ~4 Mbps
they might get now with ADSL2, but not really up
to the new benchmark.<br>
<br>
That leaves vectoring as the major difference -
which will make speeds more predictable and push a
lot more services to the right to higher speeds,
reduce the width of the fuzzy cloud in the second
diagram, but still won't deliver 50 Mbps further
than about 750 metres.<br>
<br>
<br>
Anyway, back to the original topic - I was
looking for ADSL2+ data - anyone?<br>
<br>
<br>
<br>
</div>
<blockquote type="cite">
<div class="im">
<div> <br>
Regards,<br>
- Guy.<br>
<br>
<br>
<br>
<br>
On 12/09/2013 12:17 PM, Paul Brooks wrote:<br>
</div>
</div>
<blockquote type="cite">
<div class="im"> A recent Ofcom (UK) report has
a very interesting chart of ADSL2+ line
speeds:<br>
</div>
<div>
<div>
<div>
<div class="im"> Ofcom Infrastructure
Report 2012 Update<br>
<a moz-do-not-send="true"
href="http://stakeholders.ofcom.org.uk/market-data-research/other/telecoms-research/broadband-speeds/infrastructure-report-2012/"
target="_blank">http://stakeholders.ofcom.org.uk/market-data-research/other/telecoms-research/broadband-speeds/infrastructure-report-2012/</a><br>
<a moz-do-not-send="true"
href="http://stakeholders.ofcom.org.uk/binaries/research/telecoms-research/infrastructure-report/Infrastructure-report2012.pdf"
target="_blank">http://stakeholders.ofcom.org.uk/binaries/research/telecoms-research/infrastructure-report/Infrastructure-report2012.pdf</a><br>
Figure 4 on page 11:<br>
</div>
<mime-attachment.png><br>
<div class="im">
<p class="MsoNormal">This chart is
effectively the result of the ADSL
line-sync/attenuation curve combined
with the increasing area of circles of
increasing radius around the exchange
- and demonstrates very clearly why so
many people get low ADSL2+ line
speeds.<br>
(Exercise for the reader - work out
how VDSL2 would be any different)<br>
<br>
</p>
Also scatter-plots of sync-speed with
line-length, as per Figure 8 from
another UK report:<br>
<br>
</div>
<mime-attachment.png>
<div class="im"><br>
<p class="MsoNormal">Now every DSLAM
network operator can put together
similar charts - but I'm not aware of
any stats for Australian networks,
apart from the heat maps put out by
iiNet and the <a
moz-do-not-send="true"
href="http://adsl2exchanges.com.au"
target="_blank">adsl2exchanges.com.au</a>
site, which aren't quite what I'm
looking for.<br>
</p>
<p class="MsoNormal">For all you DSLAM
operators - I would be very interested
in putting together similar charts for
the Australian networks, to see how
our copper loop network varies from
the UK network. If anyone is willing
to share data or statistics, I'm very
interested in pulling together similar
Australian charts - on a
non-identified, aggregated, anonymised
basis if you wish.<br>
Please contact me off-list - thanks.<br>
</p>
<p class="MsoNormal">Paul.<br>
</p>
<p class="MsoNormal"> <br>
<br>
</p>
</div>
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<div class="im"> <br>
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<div class="im"> <br>
<br>
<pre cols="72">--
Guy Ellis
<a moz-do-not-send="true" href="mailto:guy@traverse.com.au" target="_blank">guy@traverse.com.au</a>
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T: <a moz-do-not-send="true" href="tel:%2B61%203%209386%204435" value="+61393864435" target="_blank">+61 3 9386 4435</a> M: <a moz-do-not-send="true" href="tel:%2B61%20419%20398%20234" value="+61419398234" target="_blank">+61 419 398 234</a>
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-- <br>
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