NBN will only offer guaranteed download speeds of just 12Mbps for customers on a fibre-to-the-node service, while transitioning customers in each area from ADSL.
Late last week, NBN watcher jxeeno discovered in the latest draft wholesale broadband agreement, for business readiness testing for fibre-to-the-node, the bandwidth profile for services on fibre-to-the-node during a "co-existence period" -- where ADSL services are running alongside fibre-to-the-node services -- would only be the basic 12Mbps down, 1Mbps up service.
This means that in the 18-month transition period, typically used for moving areas from the legacy Telstra network to the NBN, customers in those areas could be limited to speeds as low at 12Mbps. This is despite the fact the government had promised, but subsequently broke, to deliver 25Mbps download speeds to all Australian premises by 2016.
A spokesperson for NBN said the company wasn't seeking to limit the speeds on offer to customers during the transition period, but was in line with the company's post-strategic review policy of not guaranteeing speeds it cannot deliver.
"As we're upgrading the copper to be capable of faster speeds, we have to take steps to ensure the change in frequencies doesn't cause interference between the ADSL and VDSL services," the spokesperson said.
"Hence taking a cautious approach with our customers, the retail telecommunications companies, and guaranteeing the delivery of 12Mbps/1Mbps."
Some customers may experience higher speeds, but NBN will not guarantee it. The spokesperson pointed to trials where NBN used spare copper lines to achieve download speeds ranging between 50 and 90Mbps while in co-existence with ADSL services.
"During the period when NBN is upgrading a suburb with ADSL to VDSL2 speeds will not be limited to 12/1Mbps. During this so-called 'co-existence period' line speeds on the NBN FttN service will still be substantially faster than those being delivered via ADSL2+ from the exchange," the spokesperson said.
"Once [the] switchover period ends, speeds are then set to increase even further. That's because VDSL2 services operate with eight times more spectrum than older ADSL services meaning they have far greater potential throughput, and with the addition of vectoring -- that cannot be used with ADSL -- you reduce interference and therefore increase VDSL2 speeds."
In Budget Estimates hearings last week, NBN also revealed that due to the company's focus on making more premises able to order a service, the number of "premises passed" by the network under the former Labor government's metric would be slightly lower than when the NBN projected the Labor rollout model would have achieved in the same time frame.
The old rollout was estimated to have "passed" 1.357 million premised by the end of June this year, but NBN CEO Bill Morrow said the company will get "very close" to this number, but would not guarantee the company will reach it.
"The strategic review said 1.357 million; our corporate plan said 1.168 million. We are going to deliver closer to the 1.357 million, exceeding our corporate plan target for premises passed -- period."