[LINK] NBN white-elephant-to-be ...
Roger.Clarke at xamax.com.au
Wed Aug 25 11:46:58 EST 2010
When I saw the viral letter ('$60bn Fiasco'), I:
- wrote to someone who I knows more about broadband than I do
- remarked that several of the arguments are furphies, and sound
more like a Liberal Party spin-doctor than a telecomms engineer
- asked questions about two points that were unclear to me
Below is the person's answer, subsequently approved for
non-attributable distribution to interested parties.
Yes - I did see this. The fellow who claims to be an "expert" takes
fragments of truth and spins them into invalid arguments designed
more to support his political bias than any informed discussion on
A classic example is his spurious argument about contention ratios.
Of course as you move from access links into the core of the network,
you are exposed to increasing contention ratios ... but beefing up
trunk links is cheap compared to beefing up access links ... and
higher performance in the access network will provide the incentive
for upgrades in the core network. His argument here is no more valid
today than it would have been to argue 15 years ago that there's no
value in going beyond 56kbps dial-up modems because of (the same sort
of) contention ratios that existed on trunk links back then.
Similarly, his faith in wireless is wildly optimistic. He does
acknowledge contention ratios, but nevertheless goes on to intimate
that 100Mbps performance could be a realistic customer expectation.
The spectrum required to deliver this to bandwidth hungry customers
in high-density urban areas just isn't available unless cell-sizes
are reduced to ridiculously small levels (a tower every few hundred
meters). Once again, he could do well to go back and study some basic
In relation to the two specifics you asked:
>1. *does* fibre optic cable have a short life-span, particularly when
> air-strung - as claimed in the letter's section (1)?
> I ran national LAN conferences in 1984, 85 and 86, when fibre-optic
> was becoming an engineered and understood product, and I don't recall
> tripping over that claim before
Re DSL technologies - yes, they will continue to get better - mostly
as a consequence of Moore's Law and the ability to throw more
processing capacity at the task of discerning signals against a noisy
background. However, the law of diminishing returns applies ... and
Shannon's Law is ultimately one of limitation, not exponential growth.
Copper will *never* compare to fibre in its capacity, and the key to
better performance lies in shortening copper distances - that is,
pushing fibre deeper into the network.
Does it need to go all the way? Not immediately - FTTN was a credible
approach to beefing up capacity of Australia's copper infrastructure
and getting everybody to at least ADSL2+ type performance. TransACT
took fibre to within 300m of the customer, and with the latest VDSL2
chipsets can reliably deliver 80Mbps downstream and 20Mbps upstream
over its cabling. That sort of bandwidth will satisfy most people for
quite a while into the future.
But with our trading partners moving to fibre, applications that
consume higher bandwidth *will* emerge and we will be caught short as
a nation if in the long term we don't have the infrastructure to
compete. I would contend that Australia needs a plan to evolve to
predominantly fibre infrastructure - not necessarily in a short a
timeframe as eight years, but certainly sometime over the next 20
>2. Is DSL capable of much further improvement as claimed in (3) below?
> Marvellous though it's been (and, like disk-drives, I never thought it
> would improve to the extent it has), I understood that it was coming
> towards a theoretical limit, as dial-up technologies did as they
> approached 56Kbps
Re fibre life - I'm not an expert here, but I had a chat with one of
the world's leading fibre vendors. They would be delighted if the
claimed 15-year life expectancy was true, because they would have
their order books filled with replacement fibre.
Fibre deployed in Atlanta in 1975 is (to the best of the knowledge of
this company) still going find 35 years on. Some of the earliest
fibre in Australia was deployed back in 1983 and is (again to the
best of their knowledge) still going fine 27 years later. Some of the
fibre that Optus deployed nearly 20 years ago has recently been
upgraded with DWDM to support much higher speeds. The fibre TransACT
deployed aerially 13 years ago is showing zero signs of degradation,
and there's little reason to expect it to abruptly collapse in
another couple of years. Telstra stipulates a design life of 25 years
in its fibre purchases - I understand that NBNCo is specifying a
50-year design life.
Maybe we will see degradation in due course and there will be a need
for replacement - but the idea that it will all need replacing in
15/25 years is a bit of a joke as far as I'm concerned.
The other consideration is that the majority of NBNCo's cabling will
in fact be installed underground because of the conduit access
elements of the provisional deal between Telstra and NBNCo.
THE VIRAL LETTER:
'Labors NBN a $60bn Fiasco!'
'NBN - Sounds Impressive But a Costly Con Job'
I am a network architect for one of Australia 'S largest Telco's - so I
Speak with some authority on this issue.
Here are the technical reasons this will fail :
1) fibre optic cable has a maximum theoretical Lifespan of 25 years when
Installed in conduit. Over time, the glass actually degrades (long story),
And eventually it cant do it`S bouncing of light thing any more. But when
You install fibre outside on overhead wiring (as will be done for much of
Australia 'S houses, except newer suburbs with underground wiring), then the
Fibre degrades much quicker due to wind, temperature variation and
Solar/cosmic radiation. The glass in this case will last no more than 15
Years. So after 15 years, you will have to replace it. Whereas the copper
Network will last for many decades to come. Fibre is not the best
Technology for the last mile. That`S why no other country has done this.
2) You can not give every house 100Mbps. If you give several million
Households 100Mbps bandwidth, then you have exceeded the entire bandwidth of
The whole Internet. In reality, there is a thing called contention. Today,
Every ADSL service with 20Mbps has a contention ratio of around 20:1 (or
More for some carriers). That means, you share that 20Mbps with 20 other
People. It`S a long story why, but there will NEVER be the case of people
Getting 100Mbps of actual bandwidth. Not for several decades at current
Carrier equipment rates of evolution. The "Core" can not and will not be
Able to handle that sort of bandwidth. The 100Mbps or 1Gbps is only the
Speed from your house to the exchange. From there to the Internet, you will
Get the same speeds you get now. The "Core" of Australia 'S network is
Already fibre (many times over). And even so, we still have high contention
Ratios. Providing fibre to the home just means those contention ratios go
Up. You will not get better download speeds.
3) new DSL technologies will emerge. 15 years ago we had 56k dial-up. Then
12 years ago we got 256k ADSL, then 8 years ago 1.5Mbps ADSL2, then 5 years
Ago 20Mbps ADSL2+. There are already new DSL technologies being
Experimented on that will deliver over 50Mbps on the same copper we have
Now. $zero cost to the tax payer
4) 4G wireless is being standardised now. The current 3G wireless was
Developed for voice and not for data, and even so it can deliver up to
21Mbps in Australia . There are problems with it, but remember that it was
Developed for voice. The 4G standard is specifically being developed for
Data, and will deliver 100Mbps bandwidth with much higher reliability (yes,
The same contention issues apply mentioned earlier). $zero cost to the tax
5) The "NBN" will be one of the largest single networks ever built on earth.
There are only a few companies who could do it - Japan 'S Nippon NTT, BT,
AT&T;, Deutsche Telekom etc. Even Telstra would struggle to built something
On this scale. Yet we are led to believe that the same people who cant
Build school halls or install insulation without being ripped off are going
To to do it ??? Here at Telstra, we are laughing our heads off !! Because
When it all comes crumbling down, after they have spent $60+billion and the
Network is no more than 1/2 complete, it will be up to Telstra to pick up
The pieces ! (shhhh don't tell anyone, it`S our secret)
Roger Clarke http://www.rogerclarke.com/
Xamax Consultancy Pty Ltd 78 Sidaway St, Chapman ACT 2611 AUSTRALIA
Tel: +61 2 6288 1472, and 6288 6916
mailto:Roger.Clarke at xamax.com.au http://www.xamax.com.au/
Visiting Professor in the Cyberspace Law & Policy Centre Uni of NSW
Visiting Professor in Computer Science Australian National University
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