NBN Finally Brings DOCSIS 3.1 Down Under

Subscribing to the "better late than never" school of thought, NBN has finally started deploying DOCSIS 3.1 technology on its HFC plant, about two and a half years later than originally planned.

NBN Co Ltd. -- Australia's government-backed wholesale broadband provider that has run into funding problems, technology issues and construction delays -- said it has begun "enabling" DOCSIS 3.1 on the HFC portion of its nationwide network as it starts to ramp up HFC activations over the next few months. So far, NBN has activated several thousand premises for DOCSIS 3.1, with plans to cover all 3 million HFC-passed homes, or about 27% of all Australian homes, by the end of 2020.

The still-in-development hybrid NBN network consists of a mix of HFC, fiber-to-the-curb, fiber-to-the-premises, fixed wireless and satellite technologies. It's supposed to reach 11 million Australian homes by the time it's completed but only passes about 6 million now. (See Australia's NBN Seeks More Govt Cash to Cover Loss-Making Rollout.)

NBN started reselling HFC services in late June, after spending about six months optimizing the network. It expects to release around 100,000 homes and businesses on the HFC network to retailers every month through next April. "We are still in the very early phases of the DOCSIS 3.1 deployment and expect to scale up the deployment gradually over the coming months to meet our goal of full coverage by end-2020," a company spokesman said.

NBN plans to leverage D3.1 to "double the downstream capacity" of its HFC network. By doing so, it aims to avoid the need to install many new fiber-optical nodes through costly node-splitting, which cablecos typically use to reduce the number of homes served by their existing network nodes.

Surprisingly, though, unlike most cable operators, NBN does not intend to use D3.1 to boost data speeds for broadband users, at least not initially. So, rather than offer gigabit or multi-gigabit service, it does not plan to boost data downstream speeds any higher than its current 100 Mbit/s maximum.

"To date, take-up of speeds beyond 100 Mbit/s by the 1.6 million premises able to access a fiber-to-the-premises connection has been extremely low," the company spokesman said. "That being the case, NBN Co will not launch ultra-fast speeds on HFC at this point but DOCSIS 3.1 gives us the ability to do so in the future."

Instead, NBN is focusing on the operational efficiencies and customer experience benefits that the next-gen DOCSIS spec has to offer. In particular, the wholesale provider is counting on the latest DOCSIS spec to provide a more reliable and stable connection for broadband users, thanks to the spec's use of Orthogonal Frequency Division Multiplexing (OFDM) modulation technology and a more advanced Forward Error Correction (FEC) method.

"DOCSIS 3.1 will help us increase capacity on the HFC network far more efficiently than conducting new optical node splits, which will, in turn, free up construction resources elsewhere to complete the network build by 2020," said NBN CTO Ray Owen in a written statement. "In addition, we also look forward to the benefits that DOCSIS 3.1 will help bring on the operational side of the network in delivering a more stable and resilient network for end-users.”

The move comes as about 75% of new broadband users on the NBN network are opting for either 50Mbit/s or 100Mbit/s services. Overall, nearly 50% of the wholesale provider's 4.1 million activated premises now take 50Mbit/s or higher speeds.

As it has before with DOCSIS 3.0, NBN is relying on Arris Group Inc. (Nasdaq: ARRS) to supply the equipment, software and knowhow for the DOCSIS 3.1 rollout. Specifically, Arris is providing its E6000 Gen 2 CCAP device, OM4100 OptiMax segmentable nodes, CM8200B D3.1 cable modems, ServAssure NXT management platform and support services.

"It's an expansion of our original 2015 agreement," explained Dan Whalen, president of the network and cloud unit at Arris, which considers NBN one of its biggest international customers with at least 1 million broadband subscribers. "We built a comprehensive custom management solution for them … We're fully engaged."

At least one keen industry observer applauded the move by NBN to upgrade its languishing HFC network to DOCSIS 3.1 after initially trying to expand the network's reach without the new technology. "NBN Co. CEO Bill Morrow made the correct call when he stopped new HFC connections being added to the NBN whilst the HFC network rework occurred and this provided the time needed to gear up for DOCSIS 3.1," said Mark Gregory, a senior telecom and network engineering academic at RMIT University.

But Gregory worries that NBN Co will now scrimp on adding more fiber and nodes to its HFC network, hurting its ability to upgrade service in the future. "NBN Co is leveraging the benefits of DOCSIS 3.1 to speed up the rollout but this will severely limit future utilization of the HFC by consumers as demand grows," he said.

— Alan Breznick, Cable/Video Practice Leader, Light Reading