CableLabs: DOCSIS Has Lots of Gas Left in the Tank
ATLANTA -- SCTE Cable-Tec Expo -- Though PON upgrades have been a hot topic within cable engineering circles, the industry's widely deployed HFC and DOCSIS networks have plenty of legs left, according to some top engineers in the field.
"Coax does have a lot of life," Doug Jones, principal engineer at CableLabs , said here Monday during a pre-show session focused on the emerging Distributed Access Architecture (DAA). "The DOCSIS technology is not out of gas in any way, shape or form."
On that point, DOCSIS 3.1 gets HFC to 10 Gbit/s down and 1 Gbit/s up on plant built out to 1GHz. Full Duplex DOCSIS, the next step, is targeting symmetrical 10Gbit/s capacity. Jones hinted that the industry is also looking at HFC networks that will deliver services in spectrum well above the 1GHz neighborhood.
But DAA and Full Duplex DOCSIS will be working together. DAA, an architecture that will see elements of the PHY layer and possibly the MAC layer pushed out to the node, will be key to cable's ability to get gigabit capacities deployed everywhere economically and at scale, Jon Schnoor, lead engineer for CableLabs's wired technology team, said. (See Cable DAA Debuts Worldwide and CableLabs Pushes Full Duplex Forward.)
Cable's on its way. Citing some internal data, Schnoor said about 56% of US cable homes have access to 1-Gig services, up from just 4% about 18 months ago. (See Comcast Wraps Up DOCSIS 3.1 Rollout and Charter Nears Gigabit Finish Line.)
To get to 100% using the new architecture, CableLabs and its members have a Distributed CCAP Architecture (DCA) project well underway. The general idea is to take the traditional centralized CCAP design and "blowing that up," Schnoor said, noting that the move to a more distributed model will reduce cable's requirements for space, power and cooling.
Remote PHY is the first (and easiest) step of that process. "We had to start somewhere, and remote PHY was really it," Schnoor said.
He said the CableLabs Remote PHY specs are almost complete, with interops underway with about two dozen companies.
Eight specs for Remote PHY have been issued, with more quarterly interops slated. The aim is to get it all stable enough so vendors can start to get their Remote PHY Devices (RPDs) ready for qualification testing.
Though some MSOs are testing Remote PHY today, 2019 is when they will "ramp up" deployments, Schnoor predicted.
Work underway for the Flexible Mac Architecture (FMA)
As for next steps for DCA, CableLabs is focused on the Flexible Mac Architecture (FMA), a new name for what used to be called Remote MACPHY, and the virtualization of the access network.
With respect to virtualization, the industry is looking to define the standards and open interfaces for that abstraction layer -- a single layer based on the YANG data modeling language, according to Mike Emmendorfer, VP of systems engineering and architecture at Arris Group Inc. (Nasdaq: ARRS) and the co-chair of the FMA working group.
Among the components under consideration is a policy controller for the OSS and orchestration systems, he said, noting that the interfaces will be made to link together cable's legacy systems and the new virtualized components.
"We are defining the next-generation access network of the future, , which is the disaggregation of the CCAP," Emmendorfer said.
— Jeff Baumgartner, Senior Editor, Light Reading