Question Mark

DOCSIS 3.1+, a new option for cable broadband, may prove to be quite popular with smaller cable companies and could enable them to skip DOCSIS 4.0 or at least defer decisions about it. A key question for the industry is how popular the technology will be with major cablecos such as Charter and Comcast.

“Some of the larger operators are very committed to DOCSIS 4.0,” Jeff Heynen, vice president of Broadband Access and Home Networking for Dell’Oro Group, told Telecompetitor. Those providers have a joint development agreement with Broadcom involving DOCSIS 4.0 infrastructure and customer premises equipment (CPE), he said.

On the other hand, smaller providers that aren’t part of that agreement are “left out of the first round of being able to purchase equipment,” Heynen said.

DOCSIS 3.1+, also known as DOCSIS 3.1 Extended, will allow the smaller providers “to compete without a huge capital outlay,” he noted. “In some cases, it will be the last flavor of DOCSIS that they use.”

The New DOCSIS Option

The appeal of the new DOCSIS option is that it offers downstream speeds up to 8 Gbps, making it comparable with DOCSIS 4.0. Upstream speeds are less than for DOCSIS 4.0 but can be as high as 1.5 Gbps – which makes DOCSIS 3.1+ quite competitive with fiber broadband and with fixed wireless access (FWA).

DOCSIS 3.1+ uses DOCSIS 3.1 equipment that many cable companies already have deployed in their networks with a DOCSIS 4.0 modem. A software upgrade to the cable modem termination system (CMTS) is required, as are several other network upgrades. Nevertheless, the upgrade is less costly than deploying DOCSIS 4.0.

Heynen expects the CMTS software upgrades for the new version of DOCSIS 3.1 to be commercially available in the second quarter. Several CMTS manufacturers will be offering those upgrades.

Any DOCSIS 4.0 modem should interoperate with DOCSIS 3.1+ CMTSs, Heynen said.

He added that “there is some discussion” about CPE vendors offering a stripped-down version of DOCSIS 4.0 modems to support DOCSIS 3.1+, which would reduce the cost of the modems. He added, though, that manufacturers may not be keen on that idea as they like to minimize how many different versions of a product they offer.

What About the Big Guys?

Will the major cablecos use the new DOCSIS option? While those companies seem committed to DOCSIS 4.0, Heynen noted that there may be instances where the companies might deploy DOCSIS 3.1+ as a quick response to a competitive threat.

Potentially that could be a stopgap measure until the company subsequently replaces the DOCSIS 3.1+ CMTS with a DOCSIS 4.0 version.

It looks like Charter is planning to deploy DOCSIS 3.1+ quite broadly, based on what the company outlined for Phase 2 of the three-year network investment plans it announced 15 months ago.

Phase 2 is slated for this year and targets 50% of the company’s footprint. A diagram for Phase 2 shows a DOCSIS 4.0 modem being used with DOCSIS 3.1 equipment in the network.

Source: Charter Communications Investor Meeting

I reached out to Charter to ask if the diagram was meant to depict DOCSIS 3.1+ but was told that the company was not discussing anything about its network plans beyond what was outlined 15 months ago.

Heynen, however, said “That is definitely DOCSIS 3.1+ in a high-split configuration.”

Potentially Charter could use the technology where needed in response to fixed wireless offerings, Heynen noted.

He added that the $100-per-home network upgrade cost that Charter cited when it announced its network investment plans could not be achieved if the company were to deploy DOCSIS 4.0 everywhere.

Cable companies already had lots of decisions to make about network upgrades — when and where to deploy fiber, which DOCSIS 4.0 configuration to use, split ratios, etc. And now they have yet another option to consider.

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