NBN Co predicts that up to 10 percent of premises in footprint of the hybrid fibre-coaxial (HFC) networks will need to have infill completed before they can connect to the National Broadband Network (NBN).
As part of revised agreements with Telstra and Optus, NBN Co will take over the HFC networks owned by the two companies in Sydney, Brisbane, and Melbourne, and serve up a reported 3.7 million premises on the network.
While there is a significant amount of overlap between the two networks, there are also gaps in the networks where Telstra and Optus, rolling out HFC in the 1990s, missed connecting premises. Either the streets were skipped, or houses had not been built yet, or the companies had decided against connecting apartment buildings.
NBN Co has not quantified exactly how much work it expects it will need to do in order to connect all the missed premises. However, in response to a question on notice from Senate Estimates in February, the company said, "NBN Co expects that seven to 10 percent of the premises in the hybrid fibre-coaxial footprint will require HFC infill to be made serviceable.
"The cost of implementing this infill is yet to be determined by NBN Co. NBN Co will be able to determine the cost of implementing infill once the HFC network build commences in 2016."
This infill is significantly lower than Optus' own estimation just a few short years ago. In seeking to get the Australian Competition and Consumer Commission (ACCC) to shut down the network under the former Labor government's NBN plan, Optus said that while the network passed 2.4 million premises, 1 million premises were not serviceable, with a large percentage of these premises in apartment blocks.
NBN Co had not responded to requests for comment on whether the 700,000-premises disparity between Optus' last number and NBN Co's own number related to areas where Telstra and Optus both have HFC coverage.
NBN Co is set to go live with commercial services in 2016, and commence a full rollout in the first half of 2016, but will conduct construction trials and connect customers in Queensland and New South Wales later in the year.
"We're going to connect homes, split nodes, we're going to wire up [apartments], and go down some of the streets that may have been missed in the original rollout," NBN Co's chief technology officer Dennis Steiger told the CommsDay Summit on Tuesday.
NBN Co has submitted its draft corporate plan to Communications Minister Malcolm Turnbull, which contains rollout information for the next three years. Steiger indicated that NBN Co has not included definite rollout information about the HFC network in this plan, but that it would be finalised "very soon".
"It certainly has the potential to have a quick start, and a quick rollout. How that is going to shape specifically, you're going to see when we release our initial rollout plans, which are coming soon," he said.
"There is a process we're going through of validating how that footprint rolls out. We have to work with our partners Telstra, Optus, and also the RSPs in terms of how we're going to roll that footprint out."
Steiger said he believes that by utilising the legacy HFC technology with core network upgrades, the company could create a "truly world-class network".
"We get a tremendous amount of emails from CTOs around the world saying 'hey what are you doing in Australia? It sounds amazing'," he said.
"I've heard [the HFC] networks criticised [but] the rest of the world has networks that were built in the '70s and the '80s. These networks are fairly modern. Just looking from a high-level design perspective, they bring a lot of great qualities to the NBN."