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ATX surveyed 150 cable professionals for its annual 2050 Project survey
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70% of respondents plan to turn up DOCSIS 4.0 by the end of 2026
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Full-duplex DOCSIS 4.0 is emerging as the more attractive deployment option
If you’ve been following DOCSIS 4.0 coverage, you get the impression that the cable industry sees the technology as “The Promised Land.” And that once operators get there, they’ll be able to provide speeds to fit the 21st century broadband user’s needs – online learning, gaming, AR/VR, you name it.
But how close are cable cos to deploying DOCSIS 4.0, and how do they plan on going about it? Broadband vendor ATX Networks sought to find out with its latest 2050 Project survey.
Since 2020, ATX has conducted this annual survey to decipher how hybrid fiber-coaxial (HFC) networks are evolving and how multiple system operators (MSOs) are plotting their upgrades.
This year, ATX surveyed 150 cable professionals (which the company said was the research project’s highest participation to-date), most of whom are based in North America. Nearly three-quarters of respondents (70%) said they plan to turn up DOCSIS 4.0 by the end of 2026.
That’s pretty soon, considering only a couple of folks (Comcast and Mediacom) have started the roll out process. But the timeline isn’t that much of a stretch, according to Jay Lee, chief technology and strategy officer at ATX.
“Could there be limited scale of DOCSIS 4.0 in MSO networks [by the end of 2026]? I think by all means,” he said in a webinar last week.
“From an FDD perspective, the underlying equipment is or will be deployed, supporting bandwidth up to 1.8 GHz. So if you want to call that DOCSIS 4.0, yes you certainly can.”
DOCSIS 4.0 comes in two flavors. There’s full-duplex (FDX), which essentially allows upstream and downstream traffic to flow over the same 1.2GHz chunk of spectrum, and extended spectrum (abbreviated either as ESD or FDD), which allows operators to add extra spectrum (up to 1.8 GHz) for faster speeds.
Comcast is the most notable FDX proponent, whereas operators like Charter and Cox are pursuing the ESD route. Interestingly, ATX’s survey found FDX seems to be gaining popularity among cable cos.
FDX favored?
According to the report, 32% of respondents said they think 1.2 GHz will be the top frequency of their HFC networks, compared to 28% who believe 1.8 GHz will be the highest point their networks will reach.
ATX Marketing Director Joe McGarvey noted in the last three years ATX conducted this survey, it found the reverse: more cable companies were leaning toward 1.8 GHz. So, what gives?
A couple of factors could be in play, Lee explained. First, there could be “a disproportionate number of Comcast respondents” in the 2024 survey.
Another factor is extended DOCSIS 3.1, which essentially is a hybrid technology which combines a DOCSIS 3.1 CMTS with a DOCSIS 4.0 modem. Operators can use the technology to get up to 8 Gbps downstream and 1.5 Gbps upstream without having to go beyond 1.2 GHz.
Nearly half (42%) of ATX survey respondents said the availability of extended DOCSIS 3.1 was prompting them to revisit DOCSIS 4.0 deployment decisions and timelines.
“It really is interesting to note though even on the DOCSIS 3.1+ side of things, even as operators are looking to exploit that as a technology, it definitely involves an HFC upgrade in terms of upstream spectrum capacity,” Lee said.
“As MSOs look at that, they do plan to deploy 1.8 GHz capable active devices," he continued. "So it’s interesting that folks are pointing to 1.2 [GHz] as the pinnacle yet certainly behind the scenes, the plan is to put yourself in a place that if you go to 1.8, your plumbing’s in place.”
Lee added with 3.1 extended, operators can also “delay having to swap out taps and passives, which fundamentally would be the most significant bottleneck in terms of reaching 1.8 GHz upper frequency limitations in the network.”
The bigger picture
Dell’Oro Group VP Jeff Heynen told Fierce 3.1 extended is a less expensive option for cable cos to “achieve billboard speeds that are typically better than what fiber ISPs offer,” with the latter typically in the 1-gig or 2-gig symmetrical range.
Regarding the survey results, he said it’s important to keep in mind that only a handful of operators have committed to DOCSIS 4.0 and are part of the Broadcom Joint Development Agreement (with access to Broadcom’s latest DOCSIS 4.0 chipsets): Comcast, Charter, Cox, Rogers and Liberty Global.
While those operators “represent a large share of cable broadband subscribers,” they’re likely only five of dozens of companies who responded to the ATX survey.
“All those other operators who aren’t part of the JDA and presumably won’t have access to the initial round of D4.0 components (outside of modems) are almost being pushed into DOCSIS 3.1 extended using 1.2GHz mid- or high-split,” Heynen said.
“So, it’s not surprising to me that many operators have said that 1.2 will be the highest spectrum range they operate in, presumably before they move to fiber," he concluded.