Friday, 25 September 2020 10:26

Fibre flip 'will not fix all the problems caused by switch to FttN' Featured

NBN Co workers installing a node. NBN Co workers installing a node. Filephoto courtesy NBN Co

The changes to the NBN rollout outlined by the Federal Government on Wednesday will not solve all of the problems created by the switch to fibre-to-the-node as the main technology for the rollout, an academic from Flinders University claims.

Dr Paul Gardner-Stephens, a senior lecturer at the College of Science and Engineering, said in a post sent to iTWire that one issue was that FttN required that the nodes had power, whereas FttP only required power at the exchange and in the NBN box fixed at premises by the installers.

The government announced on Wednesday that fibre to the premises would be available to about 75% of homes on the NBN, making a total of eight million in all, by the end of 2023, with the NBN Co to spend about $3.5 billion to upgrade connections. In addition, the NBN Co said a day earlier that $700 million would be spent on business fibre zones in metropolitan areas and the regions, and $300 million to improve regional Internet services.

Dr Gardner-Stephens said: "The NBN box also has a back-up battery in it, that enabled it to be used to make an emergency call, even if the power was out at your house.

"But FttN requires that the nodes also have power. My understanding is that the nodes only have about 15 minutes of battery life, after which they are unable to carry any data or phone calls, no matter whether you have power at your house or not."

He said there was only limited information in the announcement about this, but it appeared that a local fibre loop would be added to the nodes which would still be required to relay communications back to the exchange. "So no power, no emergency phone calls," he added.

"This is potentially still important in our 'post-land-line' era, because mobile phone towers often reduce signal strength when power goes out, which can drop signal strength by two or three bars in many cases, which might mean that mobile coverage is also no longer available to some users," Dr Gardner-Stephens pointed out.


Workers from NBN Co contractor Foxcomm install a node on the corner of Parry and Darby Street Cooks Hill, Newcastle. Filephoto courtesy NBN Co

"This is an example of a 'correlated failure mode' where what we think of as two independent systems actually have a common weakness, that can cause both to go out at once. It's a bit like how COVID affected both the ability of people to get to shops, and also the alternative of online shopping."

A second issue that Dr Gardner-Stephens identified was that the costs for power and equipment needed to operate and maintain the nodes - about $2 billion a year - would not be reduced by this local loop.

"Rather, adding the fibre loops will (marginally) add to the cost of the NBN," he said. "Thus it doesn't solve the long-term costs of operating the FttN network compared with FttP. It might be that their plan is to progressively move entire FttN zones to FttP in the future, which would allow them to progressively phase out the nodes and their associated cost. However, that process would also be costly and time-consuming."

Dr Gardner-Stephens said it appeared that money would be borrowed to install the fibre loops. "Reading between the lines, it looks like this cost will be recovered by charging NBN users who want to switch. That is, those users will effectively be paying twice to get fibre NBN, as they have already paid for the NBN once through their taxes," he said, adding that regardless of how progressive governments had tried to keep NBN off the balance sheet, it remained a tax-payer funded piece of public infrastructure.

He said in this regard, it was probably a fairer and cheaper alternative to the "technology choice" program that had been pilloried for its inherent unfairness. "For example, one subscriber on a FttN node paid many thousands to have fibre to their house and then a neighbour was able to connect for a fraction of that cost, but the person who paid the large cost got no discount, refund or other benefit. "Again, this is a welcome improvement to the status quo, but is not a complete solution," he added.

On the plus side, Dr Gardner-Stephens said users would have faster speeds and, more importantly, the reliability and service of the network would be improved.

"For example, at my own home, we have had FttN for several years, and most years we have had outages of a week or more due to the aging copper that connects the node to the houses in our street, typically after heavy rain," he explained.

"Eventually it seems that NBN Co had to completely replace the copper in our street with new copper - thus effectively throwing good money after bad, when it would presumably have been cheaper in the long run to simply have rolled out fibre in the first instance. Thus where FttN was rolled out over the more fragile parts of the copper network, there will be a very real improvement in reliability."

The shift from copper to fibre would solve the "cross talk" problem that FttN had on the copper part of the network, even in its less fragile parts of the network.

"Basically the more people using NBN on the same bundle of copper wires, the more those wires interfere with each other. While the VDSL technology the NBN uses is very clever about minimising that interference, it does not completely eliminate it," Dr Gardner-Stephens said.

"And, finally, it will allow much faster maximum connection speeds. Again, our experience with FttN is that the fastest speeds we can get are about 60Mbps down and 40Mbps up. In contrast, on a fibre loop we would be able to get gigabit speeds in both directions, and in the future this could be increased to 10Gbps or 100Gbps, because only the equipment at each end would need upgrading - the fibre itself is capable of carrying signals thousands of times faster than even the best copper phone lines."

The changes would do nothing for people on fixed-wireless or satellite, he said. "Ideally NBN Co would also re-expand the footprint of FttN/FttP to reduce the demand on fixed-wireless and, in turn move the fixed-wireless footprint back out to its originally planned coverage, so that demand on the physically limited satellite service could be reduced in those parts of the country where large numbers of homes and businesses have ended up on satellite, beyond what the satellite was designed to accommodate in those areas."

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Sam Varghese

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Sam Varghese has been writing for iTWire since 2006, a year after the site came into existence. For nearly a decade thereafter, he wrote mostly about free and open source software, based on his own use of this genre of software. Since May 2016, he has been writing across many areas of technology. He has been a journalist for nearly 40 years in India (Indian Express and Deccan Herald), the UAE (Khaleej Times) and Australia (Daily Commercial News (now defunct) and The Age). His personal blog is titled Irregular Expression.

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