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DOCSIS

Cable ops urged to stoke investment in the network

CABLE NEXT-GEN DIGITAL SYMPOSIUM – DOCSIS 3.1 networks paired with upstream spectrum upgrades should give cable ops plenty of capacity to handle data demands for years to come, but now is not the time for the industry to kick back and relax.

The general history of network utilization – and the data impact of unexpected events such as the pandemic – have shown the cable industry that "we cannot take our foot off the gas," Jeff Finkelstein, chief access scientist at Cox Communications, said Thursday on a panel discussion about upgrading the cable architecture. "We need to continue driving these technologies forward."

The path forward for the hybrid fiber/coax (HFC) network includes distributed access architecture (DAA), DOCSIS 4.0, network virtualization and "10G," a broader initiative that aims to deliver multi-gig speeds, enhanced security and low-latency capabilities on multiple types of access networks, including HFC, fiber-to-the-premises and wireless.

DAA deployments have slowed down a bit during the pandemic as operators have focused on the near-term stresses to the networks as people worked and schooled from home. Additionally, there were some questions lingering about DOCSIS 4.0 – particularly around the use of Full Duplex DOCSIS and Extended Spectrum DOCSIS – that also took time to iron out (D4.0 will support both technologies, and it appears that chipmakers such as Broadband and MaxLinear will develop silicon for it).

"At times, we seem as being indecisive, but what we're really doing is setting the stage for solving these huger challenges," Finkelstein said. "It's so important that we continue down that path."

DOCSIS 4.0 on the horizon

DOCSIS 4.0 is expected to enter the picture – or at least grow in importance – when the market and the demand for data on HFC networks starts to move into the territory of multi-gigabit symmetrical speeds.

Although the first D4.0 prototypes might emerge as early as 2021, the technology likely won't be deployed commercially in a big way until the middle of the decade, Jaimie Lenderman, senior analyst, network infrastructure and software at Omdia, said in a follow-up presentation that included her latest market forecast.

Timing on DOCSIS 4.0 testing at CableLabs will depend on the emergence of silicon and reference designs from suppliers, but CableLabs is starting to set up an "adult sandbox" for future DOCSIS 4.0 product testing, Curtis Knittle, vice president of wired technologies at CableLabs, said.

In the meantime, DOCSIS 3.1 paired with a "high-split" upgrade that will bump the spectrum dedicated to the upstream to 204MHz "will be the ticket for a while," Knittle added.

Home Wi-Fi: The great leveler

And the access network is just one piece of the puzzle. Operators will also need to update their strategies and technologies used in the home, particularly around Wi-Fi and next-gen technologies such as Wi-Fi 6, said Marcin Godlewski, director of cable broadband product management at Technicolor, a top maker of DOCSIS modems and gateways. He said Wi-Fi was a weak point that the pandemic exposed when its usage grew as people worked and schooled from home.

"Wi-Fi is the great leveler," Finkelstein agreed. "You have to think well beyond the access network. It's an entire ecosystem that we need to deal with."

On the path to network virtualization

In the short-term, Cox is focused on some "light touch" work involving mid-splits that increase the swath of spectrum dedicated to the upstream to 5MHz-85MHz (versus 5MHz-42MHz), followed by a longer-term move to also raise the HFC's overall spectrum ceiling to 1.2GHz.

"That buys a pretty long runway there from a capacity perspective," Finkelstein said. He noted that Cox is strategically looking to replace outside plant passive devices with 1.8GHz technology and, later, add 1.8GHz actives.

Cox has also been busy with DAA in recent years. Finkelstein estimates that the operator has deployed more than 3,000 remote PHY devices (RPDs), with well over 1 million homes being served by RPDs today.

Cable's network future also involves the Flexible MAC Architecture (FMA), a new set of specs from CableLabs that will initially support remote MACPHY, where the MAC and the PHY are miniaturized and packed into a fiber node. Future phases of FMA will factor in a remote MAC core and, eventually, lead the industry toward full network virtualization. Boiled down, FMA will enable operators to deploy the MAC anywhere they see fit, including the hub or headend or into a node.

"With FMA, it's about options," Knittle said. "It's a huge milestone for the industry."

FMA will also tie into industry work centered on the Generic Access Platform (GAP), which will standardize the node enclosure (starting with strand-mounted housings), support interoperable service modules and enable operators to deploy more compute toward the edge of the network.

Chris Bastian, chief technology and information officer at SCTE/ISBE, said the aim is to wrap the GAP standards this year or in the first part of 2021 that will give suppliers what they need to accelerate product development.

The far-out future centers on network virtualization. Cable, Finkelstein stressed, has hit the end of the lifecycle on integrated cable modem termination system (CMTS) and converged cable access platform (CCAP) chassis, and must now start moving to a containerized, virtualized world.

"We have to build our ecosystem internally to get us to that," he said, noting that this will include not just equipment and technology but the way that the company operates and is organized. "Like anything else we've done in cable, it's a huge transition for us. But it's where we've got to go."

"This virtualization is a journey," agreed fellow panelist Robert Wilmoth, chief architect, North American service provider team, RedHat.

In an earlier keynote, Wilmoth noted that RedHat is starting to see some initial virtualization take hold with the CMTS and CCAP.

"Beyond that, I'm seeing a lot of lab work" and accelerated interest from operators about how they think network virtualization would work for them, he said.

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— Jeff Baumgartner, Senior Editor, Light Reading

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