Although it's not quite ready for Broadway yet, Full Duplex DOCSIS 3.1 is earning favorable reviews in its early tryouts and may soon advance to the big stage.

In an interview at INTX in Boston last week, CableLabs CEO Phil McKinney said the special team of CableLabs, MSO and vendor engineers now exploring the potential symmetrical multi-gig spec are making very good progress. As a result, he said the odds are looking good that the technology will advance to the more serious spec-writing stage in the next 45 days, or by the beginning of July.

"We're off and running on Full Duplex," McKinney said. "We are seeing better results than anticipated and it is looking incredibly strong."

The potential new broadband spec would enable cable operators to deliver both downstream and upstream speeds of up to 10 Gbit/s over cable's 1GHz hybrid fiber-coaxial (HFC) networks, with the potential for even higher speeds if the spectrum above 1GHz is utilized. That would amount to a huge upstream speed increase over the latest DOCSIS 3.1 spec, which can support downstream speeds as high as 10 Gbit/s but upstream speeds only as high as 2 Gbit/s.

Terming it an "incremental evolution" of the DOCSIS 3.1 spec, CableLabs announced the move to its MSO members behind closed doors at its Orlando winter meetings in February. But, as word began to trickle out about it, the cable R&D organization went public about the effort shortly afterwards even though the technology is still in the early exploratory stages. (See CableLabs Makes Symmetrical Multi-Gig Push .)

In another promising sign for Full Duplex DOCSIS at INTX last week, Nokia Corp. (NYSE: NOK) showed off the first proof-of-concept of the technology on the show floor. The demo showed how Full Duplex could deliver symmetrical speeds of 10 Gbit/s over a coax connection. Calling the prototype solution XG-CABLE, Nokia said it can deliver the symmetrical 10-Gig speeds over a 100-meter length of coax using 1.2 Ghz of RF spectrum. The solution is also compatible with DOCSIS 3.1. (See Nokia Demos 10-Gig Over HFC.)

While Nokia is not working with CableLabs yet, the company has engaged with several major cable operators in both North America and Europe to explore the possibilities of deploying Full Duplex technology, according to David Eckard, CTO of fixed networks. McKinney said he welcomed the move by Nokia, along with a similar but unrelated push by wireless vendor Kumu Networks to develop its own version of Full Duplex. (See Mobile Ops Investing in Kumu's Full Duplex.)

In one other promising sign for Full Duplex, John Chapman, a Cisco Fellow and CTO of Cisco Systems Inc. (Nasdaq: CSCO)'s Cable Access Business Unit, recently presented the industry's first tech paper on Full Duplex DOCSIS. Such an endorsement by one of the fathers of cable's original DOCSIS standard carries hefty weight.

Even if Full Duplex advances to the spec-writing phase, it will likely take the cable industry at least three to four years to craft the standard, develop the equipment for it and start deploying that equipment on its networks. So, as we've reported before, don't expect it to show up on cable networks until at least 2020 or so.

But McKinney insists that the timing might turn out to be quicker than that if all goes well. Noting that DOCSIS 3.1 took about three years to go from start to finish, he predicted that Full Duplex "will move faster than DOCSIS 3.1."

— Alan Breznick, Cable/Video Practice Leader, Light Reading