NBN Terminology

As is all too common in IT, or the computer industry if you prefer, trying to understand anything about the NBN means struggling through a world that seems to consist entirely of acronyms. NBN! See what I mean?

So, let me use this article to help. I’ll provide some of the acronyms, let you know what they stand for and explain what they mean. Although I’d like to present them alphabetically, I’ll do it more in order of appearance. By the way, this page gives a short history of the NBN in Australia.

ADSLAsynchronous Digital Subscriber Line. This gives high-speed connectivity on an existing phone line.  But the speed depended on the length of phone line between the house and the exchange. A kilometer or less allowed the full 24Mbs to download data from the Internet. Six kilometers was about as far as the ADSL signal would travel, and at that distance your speed wasn’t much better than the old dial-up modem would give. And the quality of the phone line was critical. In some areas of Australia the copper was corroded and the maximum speed was ridiculously low. It was so bad in some areas that subscribers could not get any broadband service at all.

NBNNational Broadband Network. Taking the words in reverse order, it’s a network of computers linked together; it provides broadband, or high speed, connections for users; and it covers the whole of Australia. Well, “the whole” is an exaggeration of course, it should be “most”. Avoiding the history lesson, it started with a Labor design the would provide future-proofed high speed connections at a huge cost. A change of government bought a change of design and reduced cost. Also reduced functionality but that’s not usually talked about. As of early 2018, the network is still being built.

FttPFibre to the Property. This was the first (Labor) approach. Optical fibre would be laid from the local telephone exchange and connected to each property serviced by the exchange. It gave everyone their own separate fibre, which meant upgrading, or increasing the available speed without affecting any other network connection would be easy. It’s an expensive design of course. There are nine million residential properties in the country, all of which would, potentially, have their own fibre connection. Geography was a problem though. In the outback whole towns were too far away for fibre to be used, so the network design specified satellite services instead. But the dedicated satellite for Australia had not been launched, and buying capacity on a satellite you don’t own is very expensive.

FttNFibre to the Node. The new design called for running fibre from the exchange to a new box at the end of the street, which was the “node” it referred to. The existing copper phone lines would be wired into the nodes. So, instead of your house being kilometers from the exchange, which reduced the maximum speed available, you were a hundred meters or so which allowed the full ADSL speed. Even more if some newer technology was installed.

HFCHybrid Fibre Coax. As a cost reduction exercise, where there was an existing co-ax cable under the street delivering cable TV, that would be used instead of building a node. A lot of houses would already be connected, so that cost reduced, and less infrastructure needed to be laid. Remember, this was used in addition to Fibre to the Node.

FttDPFibre to the Distribution Point. A clumsy term which refers to the installation of an optical fibre just outside your property boundary. From there, your existing copper phone line would be used to get the connection to your house. The most expensive part of a fibre installation will always be the connection into the building, and you will have noticed that most of the non-Labor alternatives strive to reduce that cost. The short distance between house and street allowed for the maximum avalable speed, and for subscribers wanting more than the 24Mbs ADSL2+ speed, VDSL modems could be used (see below).

FttCFibre to the Curb. This is an alternative term for FttDP, which appeared quite suddenly in early 2018.  It’s still optical fibre installed just outside your house and uses the existing phone line for the last few meters.

VDSLVery high speed Digital Subscriber Line. This is a higher speed ADSL modem that will allow up to 55Mbs download speed. This has been illegal to connect to a phone line between the exchange and the property because of the interference it produces, but as the maximum usable distance is about 1500 meters, a lot of properties would not be able to make use of the speed increase anyway.

And those are the important terms, and hopefully they will help make news articles easier to understand.