CableLabs Publishes DOCSIS 4.0 Spec

Establishment of cable’s next-gen network tech standard clears path for CTOs to make decisions on virtualization and DAA

CableLabs has published the anticipated specifications for DOCSIS 4.0, the next technology standard for moving data across the cable industry’s hybrid fiber/coaxial (HFC) networks.

The new specification, which is an upgrade over the cable industry’s current DOCSIS 3.1 standard, will enable operators to deliver download speeds of up to 10 gigabits per second. Upstream speeds can approach speeds of 6 Gbps.

Importantly, DOCSIS 4.0 provides a unification of two competing technologies for moving HFC networks to 10-gig speeds. Explained here in detail in a 2017 CableLabs blog post, Full Duplex DOCSIS would combine downstream and upstream signals on a single frequency, delivering symmetrical speeds up to 10 Gbps. Full Duplex is favored by the leading U.S. cable operator, Comcast, but its stringent network technology requirements made it economically infeasible for many operators.

Extended Spectrum DOCSIS (blogged about by CableLabs in September here) keeps upstream and downstream traffic separate. But it would increase the spectrum of HFC networks to 1.8Ghz from a current level of 1.2Ghz found on the fastest networks.

CableLabs is the technology consortium for the major U.S. cable companies. And it’s serving a broader cable industry initiative called “10G,” an effort to migrate cable networks to a future in which 10 Gbps speeds power increased cloud applications, video conferencing, smart homes and distance learning—a future that is, well, here to today for many of us.

But don’t look for commercial deployments of DOCSIS 4.0 networks by operators in the months to come. Cable operators still have a glut of network capacity from huge investments made over the last five years in DOCSIS 3.1 infrastructure. These buildups enabled them to offer customers the 1 Gbps speeds, the ceiling for which consumers are no where near bumping into just yet.

But DOCSIS 4.0 does give cable industry engineers in purchasing roles clarity on how to move forward in a network technology realm being disrupted by virtualization and Distributed Access Architecture (DAA).

“With the DOCSIS 4.0 specification establishing a clear path forward, giving cable operators the flexibility to pursue either Extended Spectrum DOCSIS (ESD) or Full Duplex DOCSIS (FDX), operators can move ahead with their remote PHY and remote MACPHY deployments to solve immediate head-end and power consumption issues,” wrote Dell’Oro Group analyst Jeff Heynen, in a blog post published two weeks ago.