What Is FTTdp?

The five-letter acronym on every telco nerd's mind at the moment — FTTdp — stands for fibre to the distribution point. Sitting somewhere in between fibre to the node (FTTN) and fibre to the premises (FTTP or FTTH) in speed, cost and complexity, it's a new potential technology that may feature heavily in the future of the NBN. It promises to be cheaper than FTTP, faster than FTTN and equally quick to roll out.

Fibre image via Shutterstock

To understand fibre to the distribution point, you have to work out where it places in the hierarchy of good-better-best fibre distribution network technologies — if price is of no concern, and if your interest is only in determining which technology delivers the highest connection speeds with current hardware.

At the top is fibre to the premises, using a gigabit passive optical network that runs from each house in a street (with each street its own local area network), to the drop fibre to the fibre access node to the point of interconnect — fibre all the way along the line from start to finish.

At the bottom is fibre to the node, which replaces the majority of copper in the traditional exchange-to-premises run with fibre and installs a powered node (for up to 384 users), but that uses copper for the "last mile" (actually around 400m at most) between the node and each house on a street.

Fibre to the distribution point brings the fibre almost to users' doorsteps, with the distribution point in the name referring to the individual junction box in the telecommunications pit in the street outside each property. With fibre running to within metres of the property, and therefore metres of the first connection point within a premises, FTTdp brings fibre much closer than FTTN, and almost as close as FTTP. This means near-gigabit network speeds can be achieved over the very short run of copper between premises and pit, and an upgrade to full fibre to the premises is easily possible in the future.

Crucially, FTTdp has been found to be relatively affordable — significantly more so than fibre to the premises, the full-fat option that requires fibre cable installation within individual properties. With the average FTTP installation costing $4400 per premise and FTTN costing $2300, fibre to the distribution point is only a few hundred dollars more expensive than the cheapest FTTN build-out per property.

"Skinny fibre" is a big part of the FTTdp plan. Around a third of the diameter of the green optical fibre used for the majority of the NBN's fibre rollout, and with a third of the optical fibres inside, skinny fibre is still capable of gigabit-plus speeds but fits through telecommunications network ducts that can be blocked by larger cables — which require expensive and time-consuming remediation work.

FTTdp trial rollouts so far have used skinny fibre to reduce the time and complexity of the construction. Although not as future-proof as the larger-gauge fibre, skinny fibre is still optical in nature and can support speed increases with a relatively straightforward upgrade process; in any case, it's massively superior to copper in current and potential bandwidth, and can be upgraded to FTTP in the future.

Currently running in a small, three-month trial in 30 premises in two locations in Sydney and Melbourne, the government-run company building the National Broadband Network says that its plan is to use the FTTdp technology to replace some — but not all — FTTN rollouts, as well as some fixed wireless locations.

The Labor opposition is widely expected to bring a largely-FTTdp solution as its NBN plan to the next Federal Government election, while the Liberal government believes its multi-technology mix its on the right track — although it does plan to introduce FTTdp in its rollout from the end of next year.

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