What, exactly, is the purpose of the National Broadband Network in relation to the following words? Enable. Suffice. Support. Demand. Need. Desire. Encourage. Surpass. Lead. Follow. Enhance. Boost. Revolutionise. Now keep those words in mind as you read the report “Domestic bandwidth requirements in Australia: A forecast for the period 2013-2023” from researchers at Communications Chambers, the modelling that underpins the government’s NBN cost-benefit analysis.

The modelling reckons that a decade from now, the median Australian household will be demanding internet download speeds of a mere 15 Mbps. Only households in the top 5% of internet usage will demand “43 Mbps or more”. That’s achievable with the latest copper-based technologies — provided everything works as advertised, and the “or more” bit isn’t too more-ish. And that means they’ll all be happy with Malcolm Turnbull’s Internet of Every Technology that’s Not Fibre to the Premises because that’s Labor and Wrong (IoETtNFttPbtLaW).

“Mission Accomplished”, right?

Perhaps not.

Communications Chambers has used a sophisticated-looking model, using 16 household types with varying numbers of adults and children. Three types of TV usage (SD, HD or 4K). Four levels of individual internet usage. That’s 192 different household types all up. They’ve looked at the applications everyone in those households might use, how often, and how much internet bandwidth they need. They’ve tried to take into account the way different types of usage would interfere with each other, to give a peak internet speed requirement for each household. And finally they’ve looked at how that usage would grow over time.

The resulting projections are substantially lower than others we’ve seen:

“A 2023 median demand of 15 Mbps may seem low, but needs to be seen in the context of the continuing benefits of video compression, and the fact that 58% of households only contain one or two people. Consider two people both surfing, both watching their own HD TV stream while each having a video call. Even this rather aggressive (and rare) use case only requires just over 14 Mbps in 2023.”

As The Register noted, that’s a rise of less than 50% over 10 years, a compound annualised growth rate (CAGR) of just 4.14%. By comparison, Cisco’s Visual Network Index predicts a CAGR for 2013 to 2018 of 30%.

Now every model is only as good as its assumptions. You could argue with Communications Chambers’ assumption that each household uses half its total internet consumption in some random four-hour “busy period”, or that children use half the bandwidth of adults, or that low-/medium-/high-usage households exist in the ratio 40/40/20, or that video compression will get better at a certain rate, or whatever. At least they’ve stated their assumptions — although we don’t have the computer model to play with, to see how changing those assumptions affects the result.

But the key problem is the overall assumption that we’ll see a gentle, incremental growth in internet demand — whatever its rate for individual application — based on the kinds of things we’re doing on the internet today.

During a digital revolution, they seem to have missed the revolution part.

As just one example, the model completely misses the Internet of Things (IoT) , which will add billions of new devices to the internet in coming years, as everything that can have smarts built into it will do — from airconditioners and light bulbs to toys and medical sensors. Indeed, the report almost seems to deny its existence as a concept: “The number of internet-capable devices may carry on rising, but as a practical matter a person is only going to be able to use a certain number simultaneously.” Now many, perhaps most, IoT devices will use tiny amounts of bandwidth, but it all adds up. It seems perverse at best to leave it out. What else has been forgotten in this model? This brings me back to those words in the opening paragraph.

If the NBN is built merely to cope with an incremental growth on what Australia as a society does today, then doesn’t that mean it’ll be incapable of supporting any revolutionary change that a massive increase in household internet bandwidth might bring? Previously I’ve written that the NBN is too bold for timid Australia. In response to a recent speech by Australia’s chief scientist, I reckoned that Australian science and technology needs its own Team Australia.