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On 23/09/2010 3:42 PM, Matthew Moyle-Croft wrote:
<blockquote
cite="mid:374115D2-9114-4A61-AA47-FFD3B8B9BB38@internode.com.au"
type="cite"><br>
<br>
<div>As an exchange based technology it's not terribly interesting
except for CBD exchanges and quite short loops. VDSL2 uses about 6x
as much power per port, especially if you want the higher speeds, so,
given the limitations on heat/power in TEBA, you can get a lot less
ports per rack. But, for CBD exchanges with short loops, it would
have been pretty good. </div>
<div><br>
</div>
<div>I'd have been happy if it was deployable, then at least we'd
have a choice where it made sense - certainly the bonding technologies
which can deal with cross talk are quite interesting to deliver good
speed, but, I suspect it'd be mainly for inbuilding or short loops to
business rather than residential unless we went for a cabinetised or
subloop unbundling model. <br>
</div>
</blockquote>
<br>
The bonding techniques - or at least the Dynamic Spectrum Management
techniques and 'phantom circuit' methods that Alcatel-Lucent and this
latest Huawei release is all about - require all copper lines in the
bundle to be driven from ports on the same DSLAM, and currently on the
same linecard of the same DSLAM. In a ULLS world where each pair can
be driven by a different DSLAM and is unsynchronised with the others,
DSM falls down - so do you want an exchange MDF to be monopolised by a
single DSLAM operator to enable that provider (only) to provide
DSM-bonded VDSL2 in the area?<br>
<br>
Also in the context of an exchnage - the 400 metres starts at the VDSL
DSLAM port. By the time the signal has travelled from the DSLAM
linecard through the cross-connect cable to the MDF, down the MDF to
the line-side, and then to the outside wall of the exchange, you could
easily lose 150m of that distance just inside the exchange building. In
a CBD exchange, with TEBA space on multiple floors, the distance lost
inside the building is probably the worst case of all - sooo - is there
a sufficient number of potential customer buildings within ~200 metres
of the exchange outside wall (allowing a few tens of metres inside the
customer building for risers etc)??<br>
<br>
VDSL2 is a great technology for FTTBasement then
inbuilding-copper-up-the-riser deployments - not so much from
exchanges, even CBD ones, I think.<br>
<br>
Paul.<br>
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