[LINK] No batteries required in new broadband plan

Robin Whittle rw at firstpr.com.au
Thu Apr 11 13:53:48 AEST 2013


> <brd>
> The headline (and maybe the story) is a bit misleading. It only
> refers to subscribers and exchanges. Don't know what happens at the
> nodes though.
> </brd>
>
> No batteries required in new broadband plan by: Fran Foo
> The Australian April 11, 2013
>
http://www.theaustralian.com.au/business/in-depth/no-batteries-required-in-new-broadband-plan/story-e6frgaif-1226617728606

The VDSL driver-receivers for each copper pair will need considerable
power.  So will the switching electronics between the fibre driver and
the multiple VDSL drivers.  Ideally there would be two fibre pairs to
the cabinet, going via different routes.

There's no reliable way of supplying this power over many kilometres
along with the fibre.  It might, in principle, be possible over a few
km, but this would require high voltage cables with their safety and
water ingress problems.

There needs to be a long-life lead-acid battery to power the node for 12
hours or so during local power outages.  This needs to be kept cool and
will probably need a little ventilation, so that corrosive gasses don't
build up in the cabinet.  Solar power would require large arrays of
panels - and these cabinets will always be in areas served by the power
grid.

The cabinets would need to be cooled in summer.  Failures in electronic
devices and assemblies rise exponentially with temperature.  Daily
cycling of temperatures will drive metal fatigue in the crappy tin-based
solder which is now widely used, due to EU RoHS regulations.

There's no way of reliably keeping water out of such cabinets if they
are submerged, with so many thick, typically old, 50 pair and greater
twisted pair copper cables coming into them and with a need for airflow
to get rid of heat when the Sun is beating down on the cabinet itself.
They can't be sealed so they will be destroyed by floods.  Many or most
places are not flood-prone, but anywhere that is, I think these cabinets
should be mounted on poles or embankments or whatever well above the
highest possible flood levels.


My concerns about the NBN include:

  1 - It is a legislated monopoly, with Telstra's copper network
      and the HFC cable networks being decommissioned (or do the HFC
      networks still carry TV, but not Internet?)

  2 - It is very expensive, at a time when most people in built-up
      areas get perfectly good Internet via ADSL or perhaps HFC.

      Dedicated terrestrial wireless links could probably take up
      a lot of the slack such areas where there is insufficient
      good copper pairs, and in some country areas.

      I do not think it is the tax-payer's responsibility to ensure
      everyone in the land has high-speed low-latency broadband.
      We may choose to do so to some extent, but that doesn't
      mean we have to give the majority of the people fibre.  We
      can't give low-latency (needed for VoIP) connections by
      satellite.

      Likewise its not the taxpayer's job to ensure that no matter
      where people live it only takes them 10 minutes and a few
      dollars worth of petrol to drive to a good supermarket,
      doctor, hospital, school, cinema, library, theatre,
      swimming pool etc.

      I would rather see the money being spent on teachers at
      kindergartens, primary schools and secondary schools, with
      better funding for all public schools.  I think the current
      funding arrangements suck the life out of public schools and
      lead to generally much worse outcomes than should be the case.

      Provision of medical and dental care outside the major cities
      is also a significant problem, worth spending taxpayer money on
      for reasons of preventative health and to reduce population
      pressures in the biggest cities.

      Also I would rather see money being spent on preventative
      health and on government research into drugs which are not
      likely to be patentable, but would nonetheless be effective.
      Not least of these would be making the most of natural
      antibiotic substances such as tea-tree oil, finding out what
      the various constituents do developing refining and synthesis
      techniques and testing the resulting compounds carefully.

I think the NBN's proposed mix of GPON FTTP, dedicated wireless and
satellite links is the best long-term technical solution, without crazy
amounts of fibre-laying to country areas.

GPON requires no power and has no electronics.  I recall that the single
fibre can go for 15km or more before being split into 32 or so fibres
for each home or office.  These fibre cables and the splitters can be
sealed against water.  Being non-conductive, they are less of a concern
with lightning than copper wires.

The existing copper network goes for 3 to 6km in the suburbs (very
roughly, my guess) and longer in country areas.  ADSL performance falls
off with distance, especially over 3km or more, and there are potential
problems with crosstalk, water ingress, poor cable quality, the drop
line to the house not being twisted pair etc.  There's an ADSL distance
vs speed chart, originally made by Internode in 2007, at:


http://www.warcom.com.au/blog/informative/what-does-snr-line-attenuation-really-mean/

Somewhat thicker cables are used in some country areas, which extends
the distance a little.

Both GPON and the existing copper network have no electronics in the
street - and so no requirement for power.

Today's ADSL or fixed wireless is plenty good enough for most telework,
social use of the Net, WWW access, VoIP etc.

The speed advantages of GPON or VDSL (Fibre to the Node) would include:

Downstream:  Real time higher definition video and much faster file
download.  Much better for video conferencing.

Upstream:  Essential for video conferencing.  Faster for uploading to
remote web-servers.  Enables servers and the like to be run faster or
better from the home and/or office.

Both would also aid real-time gaming and at-home cottage industries
concerning video (most likely sex-related services) and filesharing /
piracy of movies.  However I don't think tens of billions of dollars
should be spent by anyone but these people on facilitating this.

It would be good, but not essential, to have GPON or VDSL, but is it
worth the huge expense of GPON and destroying competition?  Is it worth
spending somewhat less for the lower performance, much higher
maintenance cost, VDSL?

There's still the potential for competitive Internet access via 3G
networks, with whatever priority over voice traffic the carriers choose
to offer.

I think VDSL would be less reliable than GPON and the current copper
network with ADSL.

Nor is it clear to me that in the absence of NBN-scale expenditures that
more money would go into schools, teacher training and especially
teacher salaries.

Whoever pays for the NBN initially, taxpayers and users will eventually
need to pay for the whole thing.  Launching two new satellites to cover
200,000 premises with higher speed (but still long-latency) connectivity
is expensive compared to using existing satellites at lower data rates.

I am not sure what to think.  At least the NBN's mix of GPON, dedicated
wireless and new satellites is technically excellent and relatively low
maintenance.  It would be a good piece of infrastructure.  It involves
much less electronics than VDSL - and has no cooling fans, batteries or
large flood-prone, car-crash-prone cabinets.  I am opposed to
electronics in cars and in the street.

 - Robin




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