Tuesday, 6 November 2012

NBN: Mr Turnbull's "fact-checking" - still poor?

Mr Turnbull's CommsDay 2012 address is punctuated with statements labelled as "fact".

What happens when you track down just one of the odd-sounding "facts" - that the most robust, best protected and best engineered parts of the cable-plant are the most fault prone, hence replacing them will drastically reduce maintenance costs?

It isn't true, something quite different was said: "faults" aren't just broken cables or joints, they can be cable-plant that can't support numerous ADSL services.

It would seem that Mr Turnbull learnt very little from the 2009 Godwin Grech email fabrication that cost him the Liberal Leadership (and the rest of us an early Carbon price). He seems to still not enquire after odd-sounding "facts", but goes public with them.

Here are Mr Turnbull's words, citing Graeme Lynch, the CommsDay editor, as an authority:
A third example of fantasy triumphing over fact is the tired refrain we constantly hear from the pro-NBN participants in the debate that by utilizing parts of the copper network, the Coalition’s proposed changes to the NBN will ‘lock in’ high copper maintenance costs.

As I’ve pointed out countless times, Senator Conroy has already locked in a fair chunk of these costs in – for the next 20 years at least, thanks to the contract for the USO he signed with Telstra earlier this year.

Let me quote Grahame Lynch on this matter:
“Witness this week’s debate about the allegedly high maintenance costs of FTTN compared to FTTH, sparked by BIS Schrapnel and fanned by business commentator Alan Kohler. Under the current NBN plan, the most expensive part of the copper network—that in rural and remote Australia—will be retained and funded by industry levies amounting to nearly $300m annually—nearly half the alleged cost of maintaining the entire national copper network today.

And of course, under FTTN, the most fault prone parts of the copper network—the bundles of copper that feed into exchanges, not individual access lines—would be replaced by fibre.” [7]
I have never seen this point acknowleged by the likes of David Braue, Nick Ross, Renai Le May or the other so called specialist commentators in this space.  Or by Alan Kohler or John Durie.
Below is my traceback to the original source: Dr Paul Brooks quoted in an ABC piece earlier this year.

Dr Brooks, ex-CTO of TransACT, the only group I know of in Australia to actually deploy a large-scale (55,000 premises) VDSL FTTN, is not hard to track down and it turns out, is very approachable and happy to explain what he said and how it was mis-interpreted.

How did an expert opinion on the esoteric performance characteristics of cross-talk and mutual interference of ADSL/VDSL signals, where the "worst" interference occurs in the bundles near the exchanges, get translated by Mr Turnbull into "the most fault prone parts" being the most expensive to maintain, and being avoided in a FTTN network?" How did Mr Turnbull start referring to cable faults and maintenance costs, when the source article never mentioned cable faults?

Because issues affecting Telco networks are subtle and unintended interpretation of sentences, edited down for publication, can result when read by a wider audience, less aware of the complexities.

The key misunderstanding came from Graeme Lynch at Comms Day, who somehow read the term "worst" in the original article and translated it to "the most fault-prone", when it wasn't referring to faults at all. It referred to the degree of natural cross-talk interference between wires. Lynch mis-read the original piece creating a "fact" about cable faults and cost of maintenance where there was none. Mr Turnbull then repeated this incorrect "fact" in his speech - ironically, at the CommsDay conference.

To DSL experts, the target audience of CommsDay, the word "fault" has multiple meanings, they would not necessarily have jumped to the conclusion "physical wiring or joint fault" when reading "worst".

Dr Brooks directed me to look at the original piece by Richard Chirgwin and read it more closely.

The piece clearly discussed "poor-quality" in terms of "radio frequency transmission properties", especially mutual interference of excessive numbers of xDSL circuits in large cable bundles, NOT "poor physical condition" or "poorly jointed".

 This was always known to be a problem with large-scale deployments: ADSL/VDSL is a 'hack' based on a number of "best-case" assumptions that don't scale up. That is fundamental to its design. It's OK as long as just a few people use it, but if everyone wants it, then it not only fails to perform, but cannot perform.

Graeme Lynch is correct when he describes the high-density cable sections as "fault prone": ADSL services are adversely affected.
I was puzzled by the comment and read it as "physical problem needing correction" - in exactly the same way as Mr Lynch and later Mr Turnbull seemed to understand it.

Dr Brooks, as cited by both Richard Chirgwin and Graeme Lynch is exactly correct:
In an FTTN with short-distance rules, the amount of mutual interference, and hence performance as speed and errors (a.k.a. 'service quality'), of the smaller cable bundles is massively better than our current 5-8km ADSL 1/2, with 75% at least over large cable bundles.
An FTTN network with an 800m rule will not use the large cables that are causing ADSL users cascading problems as more people connect with ADSL. This does not affect the maintenance costs of the copper Customer Access Network, unless ADSL faults requiring circuit rerouting or compensation are included.

In a short-distance FTTN, Radio Frequency transmission problems will still exist, but most of the least suitable cable will be eliminated and replaced with the fibre backhaul.

Nobody I asked knew of any breakdowns of physical cable-plant maintenance costs. Telstra may have them internally or only be aware of the aggregate amount. With the copper Customer Access Network slated for decommissioning, they have little or no incentive to identify frequent faults and undertaking remedial action, including installing new cables.

The mutual interference and line compensation problems don't evaporate when using 10- and 25-pair cables, especially when every pair carries VDSL signals and many of those cables are co-routed, and/or connect on "street pillars". The Radio Frequency transmission and coupling around the inside of the closed metal tube that is a pillar connecting 50 or more pairs will be pretty spectacular.

In summary, responding to Mr Turnbull's question:
It's of no consequence that many NBN/FTTN commentators don't "acknowledge" this point on old cable-plant being bypassed because it doesn't matter, on the data we have, it doesn't change maintenance costs materially.
Everyone who talks about short-distance FTTN deployments specifically headlines "Conditioning the copper network" as a major work-item and discusses achievable stable data-rates possible with saturated xDSL use. The TransACT solution was to run new, unjointed "Cat 5" cable to premises.

Many problems in long-distance ADSL are irrelevant in these short-distance deployments: but who cares, it's a moot point because nobody is doing it in Australia.

[Graeme Lynch, 22-Aug-2012]
And of course, under FTTN, the most fault prone parts of the copper network—the bundles of copper that feed into exchanges, not individual access lines—would be replaced by fibre.
[Richard Chirgwin, 26-Jul-2012]]
Copper quality

I took some VDSL questions to an acknowledged expert, Dr Paul Brooks, a consultant who is a member of several Communications Alliance working groups. Among other things, Dr Brooks helped craft the deployment rules that govern how ADSL2+ services are offered today.

Many people criticize VDSL2 FTTN because it depends on poor-quality Telstra copper, but having analysed the tests that helped formulate the ADSL2+ deployment rules, Dr Brooks gave the issue less emphasis than many others I've spoken to.

His reason is this: much of the "worst" of the copper network isn't in the one-or-two cable runs that connect individual premises. It's in the very large bundles of 100-plus copper pairs exiting Telstra exchanges - and these would be replaced by fibre.

An FTTN could eliminate the estimated billion-dollar annual bill spent on maintaining the copper - but only if it really did eliminate those copper bundles. Doing so would create a new set of problems relating to stranded infrastructure, regulation and competition, which I'll deal with now.

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