[AusNOG] Telstra starts VDSL Vectoring trials

[Paul Brooks]

On 23/09/2013 12:07 PM, George Michaelson wrote:
> interesting my arse! George, they're the vendor who proposed the standard!
>
> you've seen Simon Hacketts piece on whirlpool where he makes it explicit vectoring cannot work in out competitive environment? it demands re-centralization of the copper because it uses the same RF space as ADSL to do slightly different, but incompatible, modelling of noise.
>
> Its one or the other: entire D/SLAM replacement required. the whole bundle does one, or the other.
There are two different issues, which need to be addressed separately, but are often
confused - but they lead to the same result in the end.

Some existing nodes (e.g. some RIM cabinets) are dual-fed with fibre and copper from a
nearby exchange - some exchange copper passes through the node.
When you have exchange-connected ADSL2 and node-fed DSL (including ADSL2+) in the same
binder, bad stuff happens because of the stronger/closer transmissions from the
node-fed line-cards drowns out the exchange-fed signals, so exchange-fed lines
(typically ADSL2) suffers.
This happens regardless of whos equipment it is - this effect doesn't require
centralised control of the copper, but it does require that people with DSLAMs in
exchanges recognise that their signals might be drowned out to the point of
unusability by people with DSLAMs in nodes - or the people with DSLAMs in nodes need
to be required to reduce their signal strength, which is the current situation.
This isn't a problem in purely fibre-fed nodes, and isn't a vectoring problem - ADSL2
can coexist with vectored VDSL2+ in pure fibre-fed nodes.

Vectoring however, does require centralised single-DSLAM-operator control of all
lines, as the same DSLAM vector CPU needs to do the NxN anti-phase interference
calculations and coordinate all lines. This has nothing to do with presence of ADSL,
and is true even in purely fibre-fed nodes which don't have the  near/far problem
above. In essence, vectoring requires ULLS access to be repealed for vectored copper
cables.


>
> here be (regulatory) dragons...

Yup - the repeal of ULLS declaration being just one of them.



>
> -G
>
> On 23/09/2013, at 10:42 AM, George Fong <george at lateralplains.com> wrote:
>
>> Looks like they have started down the track.
>>
>>
>> http://www.afr.com/p/australia2-0/telstra_targets_billion_dollar_nbn_X8Wul0CVmC2TossqGfpqMP
>>
>> Interestingly, they are using equipment from Alcatel-Lucent.
>>
>> Cheers
>> g.
>>
>> -- 
>> <siggeorge.png>
>>     Just remember, wherever you go .... there you are. 
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