Midco and GCI are among the operators that will push the limits with DOCSIS 3.1 before considering a bigger leap to DOCSIS 4.0.

Jeff Baumgartner, Senior Editor

September 27, 2022

7 Min Read
Some cable ops will play the waiting game with DOCSIS 4.0

Major US operators such as Comcast and Charter Communications are plowing ahead with plans to roll out DOCSIS 4.0. But it's also becoming clear that several others are content to play the waiting game as they instead squeeze more capabilities out of their existing DOCSIS 3.1 networks.

"I think every operator is in various stages of their evolution of HFC [hybrid fiber/coax]," Pao Lo, vice president of network engineering at Midco, said at a Light Reading-hosted breakfast session at last week's SCTE Cable-Tec Expo in Philadelphia.

Midco's current path is to build capacity on its DOCSIS 3.1 network to 1.2GHz and pair it with a "mid-split" that expands the amount of spectrum dedicated to the upstream to the range of 5MHz-85MHz (up from a legacy range of 5MHz-42MHz).

Figure 1: Omdia's Jaimie Lenderman (far left) moderated the panel session that also featured (from left to right): Victor Esposito, GCI; Colin Howlett, Vecima Networks; Pao Lo, Midco; Jay Lee, ATX Networks; and Jon Schnoor, CableLabs. (Source: Jeff Baumgartner/Light Reading) Omdia's Jaimie Lenderman (far left) moderated the panel session that also featured (from left to right): Victor Esposito, GCI; Colin Howlett, Vecima Networks; Pao Lo, Midco; Jay Lee, ATX Networks; and Jon Schnoor, CableLabs.
(Source: Jeff Baumgartner/Light Reading)

Lo said Midco, an operator serving parts of Minnesota, North Dakota, South Dakota, Wisconsin and Kansas, is also exploring a possible "high-split" that would extend that upstream spectrum range to 5MHz-204MHz. But the operator is content to wait on future developments on DOCSIS 4.0, or consider possible other options.

"I think fiber is the end game," Lo said. "Ideally, we'd love to get to fiber, but we have a legacy plant that we have to upkeep and also be able to maintain competitiveness."

GCI, Alaska's top cable op that has already unleashed 2-Gig (downstream) broadband services, is also focused on 1.2GHz plant and a move to a distributed access architecture (DAA), a prerequisite for DOCSIS 4.0. Replacing taps, updating nodes and getting other 2GHz-capable technologies and products into the field "is half the battle," Victor Esposito, GCI's VP of architecture and engineering, said.

Beyond that, GCI will explore its future fiber and DOCSIS options. Esposito said he's hopeful the industry will find more cohesion with respect to the two options for DOCSIS 4.0 – Extended Spectrum DOCSIS (ESD) and Full Duplex DOCSIS (FDX).

Similarly, Midco has "no definitive plans on DOCSIS 4.0," Lo said. However, the company is leaning toward ESD, an option that envisions an HFC network built to 1.8GHz while continuing to keep upstream and downstream traffic in separate, dedicated spectrum. By comparison, FDX, an option favored by Comcast, will use "echo cancellation" techniques for an FDX band that allows upstream and downstream traffic to occupy the same block of spectrum.

"I look at it as an operational issue. Both technologies work," Lo said of ESD and FDX. "But it's not a big leap, in my opinion, going to an ESD-type of architecture. It's kind of more of the same on that aspect."

Shifting to an FDX architecture, he argued, could involve some retaining of field personnel and changes to broader operations.

"Right now, we're waiting to make a decision on that [DOCSIS 4.0]," he said, reiterating that the current path is to support a 1-Gig upstream using a future high-split on the DOCSIS 3.1 network. "Right now, if we had to lean one way, it would be leaning ESD for now. We're putting building blocks there for 4.0 so that we can pivot."

Jay Lee, chief technology and strategy officer for broadband access at ATX Networks, agreed that DOCSIS 3.1, when paired with upstream split upgrades, has plenty of gas left in the tank. But ESD with a high-split represents a "perfect transition into DOCSIS 4.0," he said.

"We believe there's a lot of life [left] for DOCSIS 3.1," said GCI's Esposito.

Is there a need for symmetrical speed?

The cable industry is feeling competitive pressure from telcos and overbuilders that are offering multi-gig symmetrical speeds on fiber-to-the-premises (FTTP). Cable operators will need to decide if matching up with those billboard speeds makes sense, since network traffic remains largely asymmetrical, despite the impact on the upstream during the pandemic as people worked and schooled from home.

Some on the panel argued that reliability of the access network and home network has become as important as the raw speeds they are marketing to the masses.

GCI offers 2-Gig now, but "we're starting to see a crossover between speed and reliability," Esposito said. "Everyone wants to drive a Lamborghini around ... but what everyone really wants and needs is a car that starts every time you get in it."

"Customers just want [broadband] to work at the end of the day," Lo said, noting that Midco is also putting greater emphasis on supporting the customer's home network. "Who cares what the access networks look like – if it's symmetrical or not – if it's providing enough bandwidth for their needs?"

ATX's Lee said cable's upstream will need to be "touched up a bit" with DOCSIS 3.1 enhancements and, later, with DOCSIS 3.0. "But, inherently, asymmetry will always be there," he added.

DAA deemed a critical move

Regardless of that future state of HFC, Colin Howlett, CTO of Vecima Networks, said it's important for operators to take the plunge on DAA. DAA, he points out, will pave a path to DOCSIS 4.0 but also put operators in position to extend fiber-to-the-premises connections where they are needed.

"You know the competition is coming from a speed perspective from fiber overbuilders and other competitors," he said.

Lee also touted the baseline benefits of going to DAA, including both speed and overall reliability.

"I think a lot of what MSOs need to prepare to offer is beyond the speeds and feeds argument and things like low latency DOCSIS and other tools that are available within DOCSIS to harden your network and to ultimately get to a reliable service," he said. "DAA is obviously a huge benefit towards that."

CableLabs, meanwhile, continues to focus on the new Flexible MAC Architecture (FMA), an approach that enables operators to deploy DAA with the media access control (MAC) element deployed centrally or at the edge.

Following pandemic-driven delays, CableLabs has been able to plow ahead with FMA interops this year, with more in the plans for 2023, noted Jon Schnoor, lead architect at CableLabs. Early on, those interops have attracted several suppliers, including Vecima, CommScope, Falcon V Systems, Harmonic and Casa Systems.

Goodbye, QAM video... hello, IPTV

The panel also dug into the video implications of the HFC network as DOCSIS 4.0 looms out on the horizon. The general thought is that D4.0 will help to usher in the eventual end of legacy QAM-based video.

But the question is how operators will pursue the phase-out. Some have or might build their own IP-based video services or instead focus on broadband services that can deliver services from virtual multichannel video programming distributors (vMVPDs) or other third-party streaming services.

"There's going to be a path," Howlett said.

Lo said Midco will cap its legacy QAM-based video at some point and "do a full conversion" to IPTV. But the process, which will involving swapping out older set-tops, will take multiple years, he stressed.

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— Jeff Baumgartner, Senior Editor, Light Reading

About the Author(s)

Jeff Baumgartner

Senior Editor, Light Reading

Jeff Baumgartner is a Senior Editor for Light Reading and is responsible for the day-to-day news coverage and analysis of the cable and video sectors. Follow him on X and LinkedIn.

Baumgartner also served as Site Editor for Light Reading Cable from 2007-2013. In between his two stints at Light Reading, he led tech coverage for Multichannel News and was a regular contributor to Broadcasting + Cable. Baumgartner was named to the 2018 class of the Cable TV Pioneers.

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