NBN Co has revealed that 183,000 fibre-to-the-node (FTTN) services aren’t hitting minimum peak speeds of 25Mbps.

This is the equivalent of 7.6 percent of the company’s 2.4 million active FTTN services. It is only the second time NBN Co has revealed this number.

Back in August 2017, NBN Co first said that 54,000 FTTN users couldn’t achieve speeds over 25Mbps, equal to six percent of all active users.

That means the new set of figures, which are current as at March 4, show that the number of users that fall into this unfortunate category has risen over time.

Under the NBN statement of expectations, all premises must be capable of peak download speeds of “at least 25Mbps”.

Premises that can’t achieve that with their current access technology will likely receive a different type of connection in order for NBN Co to meet its obligations.

The number of FTTN users that can’t hit 25Mbps speeds is impacted by what is known as the co-existence period, where essentially speeds are limited for an 18-month window to stop newer FTTN services interfering with older ADSL services using shared pieces of infrastructure.

NBN Co also said that the number of users with slow FTTN services “reflected existing issues

that could cause network degradation, such as in-home wiring issues, which can affect attainable speeds.

”Remediation of these degradations would further improve service performance and therefore the results,” the company said.

“The actual experience of customers using the network, can be impacted by other factors such as their in-home set-up and equipment.”

It seems that most customers with slow FTTN services ultimately end up with lines that meet the statement of expectations.

NBN Co said at the end of last year that 1.3 percent of premises in its FTTN footprint - at least 15,000 at the time - would never reach the 25Mbps peak speed promise, and therefore would get something else.

Fixing modems

As alluded to by NBN Co, one of the causes of underperforming FTTN speeds may also be modems.

Lab test results released in February showed about five percent of modems experienced more dropouts and resyncs than they would be expected to.

NBN Co said overnight that it “estimates that approximately 1.4 per cent of FTTN/B services have modems that underperform on attainable download speeds, and approximately 0.3 per cent of FTTN/B services have modem-firmware model combinations that underperform on attainable upload speeds”.

It defined underperforming as “performing at less than 90 percent of the median VDSL2 sync rate across the modem-firmware combinations analysed.”

NBN Co also said it “estimates that approximately 0.6 percent of FTTN/B services are using modem-firmware where the proportion of unstable services is more than twice the median.”

The company continued to decline to name any of the worst-performing modems or manufacturers.