Menu Close

Explainer: the National Broadband Network (NBN)

The NBN could give all Australians access to online services. iStockphoto

The big picture

Australia’s plan for a National Broadband Network (NBN) represents one of the largest infrastructure projects in the world at present.

The estimated $43 billion price tag has stirred up substantial debate over the need for such a network, particularly one promising such high data rates – up to 100 megabits per second (Mbps) in the fastest parts of the network.

But the real potential of a national broadband network lies not so much in these headline data rates; it lies in everyone having access to it; it also lies in a raft of future services that we can’t yet fully envisage.

Looking back

When electricity was rolled out in the 19th century, it was for the purpose of powering electric lighting.

Visionaries may have had other uses in mind, but the driving force – the “business case” – was to make living and working conditions better and safer.

Who would have thought that, a hundred or so years later, modern homes would have not just highly efficient electric lighting but would be crammed with electric appliances and gadgets?

No-one now questions the need for a national electricity network. Indeed, if you are off the grid you need to be seriously self-reliant, seriously capable, or living a seriously “alternative” lifestyle.

How will the NBN work?

The planned NBN will be a massive infrastructure build primarily comprising islands (i.e. cities and towns) of “fibred-up” connectivity, linked by a backhaul network (a high-capacity link between an isolated sub-network, like those serving country towns, and the main network).

The Australian context

Only about 9% of Australia is inhabited, with most people squeezing into just 0.2% of the land mass. The proposed NBN is unique because it promises to connect the entire population of this large land mass to a high capacity network. It will do this mostly – but not entirely – by fibre.

(The United States, by comparison, is only promising to reach 98% of its population; and fibre tends to be widely used only in countries with extremely high population density, such as Korea.)

How will this be broken down?

The plan is to give 93% of the Australian population access to broadband by connecting them up to a 100 Mbps fibre network, as outlined above.

For the remaining population (often referred to as the “Last 7%”) the plan is for a wireless solution.

In practice, this will affect people living in the outer suburbs of our cities, those living in small rural towns and those situated in the vast tracts of Australia with fewer than one person per square kilometre.

Optimising for the “Last 7%”

There are two ways this will be done. For some people, the plan is for a terrestrial fixed wireless access solution of some stripe that will offer 12 Mbps downlink (which refers to the data speed from the network to the user) and one or two Mbps uplink (which refers to the data speed from the user back to the network).

NBN Co. estimates that approximately 4% of Australia’s population fall into this category.

For the remaining 3%, who live in extremely remote areas, satellite access is seen as the only option. For these people, a service offering 12 Mbps downlink and one Mbps uplink is planned.

A great deal of the cost associated with the network is in connecting to this last few per cent of the population.

How wireless access systems work

A wireless access system consists of access points (commonly referred to as “base stations” or “towers”) that users connect to. These access points, in turn, are connected to the country’s backhaul network.

It’s unlikely any mobile operator will install enough base stations to cover Australia’s most remote areas. While the technologies developed for cellular mobile wireless communications can be boosted, as distances increase, they quickly start to run out of steam or become a great deal more expensive.

The benefits

Just as sealing the roads and improving the rail networks in remote and rural areas of Australia during the 20th century allowed goods to be delivered to and from all parts of the country, a modern communications infrastructure promises to allow services to be delivered to, and provided from, anywhere.

The benefits of delivering services to such areas will be easier to imagine as more services come online: think banking and shopping, for instance.

More importantly, federal, state and local governments are also making significant moves to put more information online and to make services more readily available via web interfaces.

Taking a few steps further into the future, dealing with agencies such as Medicare and Centrelink could be done via a video conference or telepresence system as simple and intuitive as using the telephone.

For anyone who has ever tried to explain to someone on the other end of the phone which box to fill in for a particular form, a telepresence system that allows users to point, gesture or even pass the form back and forth, would make life much easier and more productive.

Similarly, moving from simply searching the web armed with a list of possible medical symptoms to actually engaging with a remote physician who can see and hear you clearly, note your skin tone and colour, see how you move and point, measure things on you, gesture and even share documents, dramatically boosts the quality and effectiveness of the medical service delivered “online”. And, of course, no-one needs to travel.

Towards “symmetrical systems”

Innovations and services like those mentioned above involve a considerable step-up in the data rates required at both ends of the network.

For services such as these, meaningful data rates from the home or office are just as important as meaningful data rates _to _ the home or office. This is what’s known as a “symmetrical system”.

The ideas and innovations in many cases are here already, developed by CSIRO and others. What has been missing is access to affordable, high speed, reliable, symmetric, communications that can handle data-rich applications.


Some Australians (presumably those living in urban areas) have said their internet access is perfectly adequate (in 2010, the Australian Bureau of Statistics reported 71% of people with an internet connection had access at 1.5 Mbps or more) and can’t imagine needing access to the 100 Mbps promised by the proposed fibre network.

But, as mentioned already, the real potential of a nationwide broadband infrastructure is not these headline data rates, but the fact that all Australians will have the opportunity to access high-speed, reliable communications at meaningful data rates.

If those data rates are also available from the home to the network (that is, that the system is symmetrical), then even more is possible.

Communications technology will not solve all of Australia’s challenges, but it will address a major one which has been with us since the beginning: distance. With a nationwide broadband infrastructure in place, will we still remember why we argued about the need for it?

This article reflects the personal opinion of the author and does not represent any official position of CSIRO

Read more about CSIRO’s research to bring broadband to the bush.

Want to write?

Write an article and join a growing community of more than 184,300 academics and researchers from 4,972 institutions.

Register now