NBN Co is expecting to spend around $80 million upgrading its hybrid fibre coaxial (HFC) network to DOCSIS 3.1, but says the costs will be “more than offset”.

“The incremental cost of moving to DOCSIS 3.1 is expected to be approximately $80 million,” the company said.

“These costs are, however, more than offset by ongoing capacity management benefits, including fewer HFC node splits and operational benefits of spectral efficiency.”

NBN Co started activating the first DOCSIS 3.1 premises in Sydney and Melbourne back in August.

It said the use of DOCSIS 3.1 would “double downstream capacity” on its HFC network, and allow the company to stop using other methods to increase capacity, such as physical and virtual node splits.

Pre-DOCSIS 3.1, NBN Co had been facing an increase in the number of costly physical node splits required to reduce oversubscription on existing HFC nodes.

Areas that were in line for node splits were prioritised in the DOCSIS 3.1 upgrade.