NBN: Turnbull's Quintuple-whammy for G.fast

Abstract: G.fast is "bleeding edge" technology, or "vapourware". It will need 20-30 times as many nodes, will need 10-20% more Fibre laid than FTTP, will need two-pairs to get 1Gbps (spares not currently available), the electronics will be 5-10 times more expensive than VDSL2, will need extensive remediation and rewiring of the copper network and will consume ungodly amounts of power doing this. The same applies to short-range wireless "picocells". They've been tried and aren't economic.

Turnbull is either technically illiterate or informed and misdirecting on a monumental scale. Which, given he has written that NBN Co is a purely commercial concern, raises serious questions about his statements under the CCC/ACL.


For around 15 years, 1 gigabit/sec over copper for 100m has been available, it's not new, nor difficult. My guess is there are 2-5 billion ports currently in-use. It's called Gigabit Ethernet, 1000BASE-T, and is the default chipset in every PC, laptop and average computing device. There are aleady 10Gbps copper links around, like Infiniband and the Apple/Intel "Thunderbolt". They either use very high-spec cables or are limited to about 2m: even in a machine room, 10Gbps Fibre ethernet is way cheaper, easier and more reliable.

The problem for Turnbull is that, as he says, "you wouldn't start from here". Real Gigabit over copper is symmetrical and starts with higher-spec cable (Cat-5a or Cat-6, Cat = "category"). The whole problem is that the telephone cabling we have does exactly what it was specified for in 1925: carries 4kHz very well. The 25,000 times faster 100MHz needed for "G.fast" is a very, very long stretch indeed.

The only way to get cheap, reliable 1Gbps over Copper on the last 100m is to run new Cables, as is done in every commercial LAN. But that's as much, or more, than Fibre - because the Copper is necessarily thicker and heavier than Fibre.

Turnbull need to answer a fundamental question:

Why is he so intent on protecting an asset, the Copper Customer Access Network, that doesn't belong to either the Government or NBN Co, but to an entity the Coalition valued so poorly, that it was sold, when he was a Minister, at knock-down prices in 2006: Telstra.

G.fast - "New Technology"

Turnbull doesn't use the correct technical vernacular for this untried, untested,  pre-production technology: Bleeding Edge. Technologists with more than 5 years experience are universally wary of big claims by any technology vendor. Most fail to perform in practice, only a small proportion of announced "revolutionary" products actually get to market, and then only a very few scale-up into volume production (like 1Gbps Ethernet on twisted-pair and 10/40/100Gbps Ethernet on Fibre.)

To run G.fast nodes in Australian conditions, the following apply:

• A 100m limit means cables can't cross roads.
• Nodes can only serve one side of the street.

• The NBN is going to roll-out 148,000 road-kilometers past around 12M premises.
• That's 12.5m per premise on two sides of the street,
• or 25m/premise down one side of the street.
• G.fast nodes will average, at most, 8-ports per node, with nothing left for expansion.

• Long-blocks, long-driveways and battle-axe blocks allow only 1 or 2-ports per node.
• The average count of ports per node will hence be much lower than 8.

• Would any rational engineering project reserved G.fast for Flats & Apartments (MDU's), as in "Fibre to the Basement?"
• NO. When 1Gbps ethernet is readily available, under 1/10th the cost of G.fast and only needs a few short runs of Cat-5/6 cable installed, a commodity these days, there is every reason to not use G.fast, or even VDSL2.

Turnbull fails to disclose the realities of his "New Technology" - it doesn't scale-up and worse:

• At a minimum, Turnbull is going to need 20-times more nodes for G.fast.
• That means digging up every single Nature strip to install both Fibre to the Nodes and Electricity to power those Nodes. This ensures colossal disturbance of every neighbourhood.
• The cost of civil works for nodes doesn't scale with size, but stays roughly constant.
• For an 8- or 12-port node, it will cost around 90-95% as much to install as a 200- to 400-port Node, or "RIM", CMUX or Mini-Mux as Telstra calls them.

• Paul Budde, a globally respected Telecomms Analyst, reports that Scandinavian Telcos, even with VDSL2, are finding they need to run more Fibre in an Fibre to the Node Network than in an Fibre to the Premises Network. These are exactly the "only experts that matter" according to Turnbull, people in Telcos doing it "for real".
• The reason is simple. The Fibre for Nodes has to be run down the street, past the houses to the node, then the copper comes back to the house.
• The nett result is that G.fast at 100m down each side of the road, will require 10%-20% more Fibre to be laid than direct Fibre to the Premises.

• As carrier frequency rises, so does the need for "remediation".
• ADSL 1 at 1.1 MHz needed little work to allow 1.5Mbps at 4,000-5,000m.
• ADSL2 at 2.2 MHz needed enough remedial work to get 12Mbps at 1500m that Telstra in 2005 noted it as their second biggest
• VDSL2 at 17 MHz and 30 MHz over 800m will need extensive line testing and remediation to reliably achieve even the lowest denominator, 25Mbps.
• G.fast at 100 Mhz over 100m won't tolerate any bad joints, any patching nor any degraded copper or insulation. "Water ingress" will likely stop the service stone-dead: an effective short-circuit.
• As DSL speeds increase, the need to "remediate" (fix or replace) the Copper increases, a G.fast solution will need a massive amount of copper replaced, negating its cost advantage over direct Fibre.

• G.fast only achieves 1Gbps is the following is done:
• "bonded pairs": two sets of wires are needed, each giving
• Virtual or "phantom" pair: an old telephony trick reborn. A third pair of wires is made
• Vectoring: very fancy, very complex "noise cancellation". In electronics, fast + complex  equals really, really expensive.
• For subscribers to get the advertised 1Gbps, they will need 2 pairs to their premises. The Customer Access Network simply doesn't have 100% spare lines installed waiting to be used.
• As soon as new copper has to be laid, it's cheaper to run Fibre to the Premises.

• The electronics for the G.fast lines, the line card, will be very complex to do the many complex calculations required, on the order of what is done in a high-def CAT scan, it also has to run very fast to handle the 100Mhz line frequency and they will not be cheap, high-volume production chips.
• The electronics, line-cards, for G.fast will be 5-10 times more expensive than even VDSL2.

• There's an iron-cald law of computing: the more calculations you want, the more power you need, the faster you want to do them, power rises quadratically (why we hit the CPU "heat-wall in 2003 at around 3Ghz).
• These fast, complex, expensive and fragile chips will also consume 10-100 times more power than VDSL2.
• The operational cost of powering these 1.25 million nodes will really be "another BIG power station." [Update: 9M lines ÷ 8 ports = 1.25 M nodes. @ 1+kWatt each = 1.5 GigaWatts]
• These chips will run hot. The normal air-cooling in street-side cabinets will be insufficient - just like the fans on laptops and PC's go into overdrive on hot days, but eventually either turn-off the computer or slow it down to cope with the heat.
• Either all these nodes will have to contain cooling systems for days over 35°C, or
• they will throttle-back speed on "hot days", even shutting down altogether.
• For every 5°C increase in "junction" operating temperature, component life is halved. These devices will need constant replacement in our environment.

• Every time you install a piece of "street furniture", you are also committing to removing it and restoring the built environment.
• The cost of the removal and disposal of the G.fast nodes has to be counted in their cost, not just "installation".

With all these negatives, one node per 8-houses, down each side of the street and disturbance everywhere for Fibre and Power, I can't see any sane Council approving their construction.

Hiding them "in-ground", in Pits, is a really, really bad idea. Pits will fill with water and they don't have good ventilation required for cooling. 240V + water + expensive electronics is a very bad combination.

The "gotcha" for G.fast is that it will interfere with FM radio - it works in the same frequency band, and those 100m twisted-pairs will make fantastic transmitting aerials. Interference with radios will be a constant and unavoidable outcome of the hare-brained technology.

All these arguments, plus others, apply to wireless "pico-cells".  "We can 'just' put up a wireless access point on every second power pole" is rubbish. A great idea until you try to do it: already has been tried by billionaire Paul Allen in California and Colorado (Ricochet) around 2000 and it failed miserably. The economics of fixed-line Fibre has continued since then to draw ahead of Wireless and Wireless-over-Phone-lines as DSL should be called.

Summary:

G.fast is a very poor technology, even if you own the Copper and want to protect that asset, which NBN Co does not.

If G.fast does turn out to be "30% cheaper to install than running Fibre" in densely-populated Europe or American cities, it won't be so in Australia. Everywhere here, Nodes have to cope with summer temps that will fry the electronics or required every node to be cooled, trebling the initial cost, doubling the running costs and decreasing the reliability of the service.

It's not even a good idea for Flats and Apartments: if you want cheap, durable and "cost-effective" 1Gpbs copper connections, run 1000BASE-T and put in new Cat-5/6 cable!
Fibre-to-the-Basement is a colossal waste of money.

At the very least, 20-times more nodes are needed than VDSL2, with electronics costing 5 times as much and 2-5 times as much 'remediation' of the existing copper and powering them will require "a BIG "power-station".

If a VDSL2 FTTN will cost $8 billion, then 1.25 million G.fast nodes FTTN will cost upwards of $50 billion.
If Turnbull isn't proposing to roll-out G.fast everywhere, then what does he mean by a National Broadband Network? Selective and highly-subsidised for the favoured few?

If Turnbull doesn't know this already, he's uninformed and incompetent.
If he does know this, then he's deliberately withholding material information when discussing a new commercial venture.