Gfast advances continue along technological and certification lines, encouraging more service providers to adopt the protocol standard. The advent of virtual plugfests enables more operators and vendors to participate in the development of Gfast products, standards and interoperability -- good news for the entire Gfast ecosystem.
That expanded universe already has an impact. Smaller operators like Hawaiian Telecom and Cincinnati Bell are dipping a toe into Gfast; larger players including BT, AT&T and nbn have already waded into deeper Gfast waters after recognizing the benefits this technology delivers for today and tomorrow. (See Gfast Gallops Into Year-End )
Once thought of as a solution that brought near-gigabit speeds to existing copper and coax wiring, operators now see Gfast as a revenue-earning, gigabit-plus step toward fiber. As they earn income from Gfast deployments within a multi-dwelling unit (MDU) or other structure, they're also literally laying the groundwork for full fiber-to-the-home by bringing fiber-to-the-basement.
Certification and interoperability testing are a big reason why Gfast sales will grow 600% in 2019, after operators have tested and piloted 32-port Gfast, said Alam Tamboli, senior analyst at Dell'Oro Group. (See Certified Gfast Products Triple in 3 Months)
To dig deeper into these processes, UBB2020 Editor Alison Diana spoke recently with Tom Starr, president of the Broadband Forum (BBF) and chairman of the ITU-T working party 1, study group 15 and participant in ITU-T Q4/15 (which wrote the G.9700/G.9701 suite of G.fast standards) and Lincoln Lavoie, senior engineer at the University of New Hampshire Interoperability Labs (UNH-IOL), which is responsible for the Gfast certification and interoperability testing.
The following is an edited version of their conversation:
Alison Diana: What roles do ITU, the BBF and UNH-IOL play in the creation of an interoperable standard with Gfast?
Tom Starr: The ITU defined the Gfast technology and wrote the standard that specifies the interface between the customer and network equipment and defined the functionality of the modems on each end of the line. Following that, the BBF wrote the management model using the Netconf/YANG model to manage the equipment and wrote the certification testing program, which defined how the equipment shall be tested. After that, the BBF selected the UNH IOL to do the testing and provide oversight to the testing and certification efforts.
Lincoln Lavoie: The UNH-IOL also contributed to the test plan design, established plugfests and certification testing, and submitted feedback into the original standard to provide clarity when necessary.
AD: Why is Gfast interop so important?
LL: From a purely technical perspective, interop future-proofs networks and provides a mechanism to ensure interoperability with products down the road.
TS: Interoperability means service providers aren't locked in to one vendor. Interop expands the choice of vendors to buy from and the ability to change vendors over time if necessary.
AD: How rigorous is the Gfast certification process?
LL: When testing broadband, we test both conformance to the specification and also whether the systems interoperate with other devices across multiple chipset vendors. When we developed the testing, the operators identified what was critical to their networks, including performance of the systems, stability and specific feature sets. We look into basic performance, each system's ability to operate in noise environments and implement mitigation features such as retransmission, fast rate adaption, seamless rate adoption, etc. We also verify spectrum control to conform to regional regulatory requirements and other in-depth sets of requirements.
AD: How does Gfast testing compare to previous technologies?
LL: I would say that Gfast testing has already been more rigorous than any VDSL2 testing we did. On Gfast, we are testing individual features more deeply than we did in VDSL2.
TS: Gfast surpassed the level of interop in xDSL in half the time. The biggest difference versus ADSL and VDSL is the Gfast industry came together with a can-do attitude. This included service providers, equipment and chipset vendors.
AD: How did you get so many products certified in such a short time? (See Certified Gfast Products Triple in 3 Months)
LL: We implemented … the virtual plugfest. In addition to in-person plugfests, we have overlaid the ability for vendors to leave their equipment at the UNH and, with remote instrumentation, be able to control tests without traveling to New Hampshire and having an in-person event. The normal in-person plugfest frequency is four to six times per year whereas with virtual plugfests, we are running plugfests roughly three weeks of each month.
AD: What comes next?
TS: First, a lot more equipment is going to be tested. Different makes and models. In the future, we will test over coax, test using reverse power feeding, test the 212a and 212c band plans, bit-rates up to 2 Gbit/s and more.
LL: We will address new features from the ITU-T and keep pace with the industry.
— Alison Diana, Editor, UBB2020. Follow us on Twitter @UBB2020 or @alisoncdiana.