Comcast has joined Charter in committing to DOCSIS 3.1 for the long term, following Altice USA’s somewhat stunning announcement last week that it would be the first U.S. cable company to deliver multigig services with an all-fiber network.

Speaking at UBS’ annual media and telecom conference this week, Comcast CFO Mike Cavanagh followed Charter Chairman and CEO Tom Rutledge in swearing allegiance to the “Full Duplex” version of DOCSIS 3.1, a technology currently under development by CableLabs that can theoretically deliver symmetrical speeds of up to 10 Gbps over HFC networks.

“In a couple of years' time, we'll have the next-generation DOCSIS, which will allow for a multigig symmetrical,” Cavanagh said. “So, that's our roadmap. Nothing changes about that roadmap. And, of course, we preserve the ability to take fiber directly all the way anywhere where it makes sense.”

RELATED: Charter’s Rutledge: We can get to 10 Gbps without going all-fiber

Comcast has been on the forefront of DOCSIS 3.1 deployment, declaring last month that it will be delivering gigabit-speed services based on the technology in 15 markets earlier next year.

“From where we sit, we're rolling out DOCSIS 3.1. We think that's the most effective and efficient way to give big speeds across the footprint most quickly, most economically,” Cavanagh said.

A day earlier, Charter's Rutledge said very much the same thing—his MSO would continue to selectively go the all-fiber route in markets like enterprise and with new construction.

“But we think we can get to 10-gig symmetrical, which is a very rich architecture, without a compete network rebuild,” Rutledge said.

For its part, CableLabs just indicated that Full Duplex is about a year away from trials … and several more years after that away from ubiquitous deployment.

"[Full Duplex is] something that's in the labs right now," CableLabs Chief Strategy Officer Ike Elliot said at an event conducted last week. "We're working with the vendor community in defining specifications on it, and we really expect to see some trials on that within about a year.”