Cable (Like the Phoenix) Rises Again
By Jeff Finkelstein
“The report of my death was an exaggeration.”
— Mark Twain, 1887
“Mine too…”
— DOCSIS, 2016
“Seriously? I’m still here…”
— DOCSIS 2019
“For heaven’s sake, enough already…”
— DOCSIS 2022
With the recent industry news showing DOCSIS 4.0 silicon getting speeds approaching 10 Gbps downstream and over 6 Gbps upstream, we stand poised to enter the multi-gigabit, multi-verse with the dawning of a new era. DOCSIS 4.0, a sixth generation DOCSIS standard, is now in the early stages of lab trials and gives direction to the 10G vision. With DOCSIS 4.0 we can see the reality of a 10+ Gbps downstream and 6+ Gbps upstream, which enables us to compete with the growing number of ISPs leveraging fiber networks, but faster and far less expensive, for similar capacities.
While exciting, it shows us that the time to plan for DOCSIS 4.0 is now. Not at a future time when we need it. Now. As in today. Putting things in perspective, the upgrades needed for DOCSIS 4.0 may extend the life of the cable network for 20 years and beyond.
Not surprisingly, many cable operators are awaiting the chance to deploy DOCSIS 4.0. For instance, in an informal survey of cable providers across the globe it was found that providers expect to pass around half of their residential broadband subscribers with DOCSIS 4.0 by 2030. In the U.S. alone, that would translate to more than ~60 million cable broadband subscribers. If that brisk rollout pace can be achieved, DOCSIS 4.0 will be more widely deployed in the early going than its predecessors.
Currently, DOCSIS 4.0 is the cable industry’s leading technology priority. At the same time, it presents several fresh challenges for the cable industry demanding technological shifts, operational changes, and spectrum growth to reach its full potential. All require careful planning with many changes needed to our EMS and NMS ecosystems. Cable operators will also need new equipment, new procedures, and new testing and monitoring tools to turn their gigabit dreams into reality. Then just for more fun, we will have to carry out extensive staff training and re-training, even as we seek to fend off challenges from competitors.
History repeats itself. Again.
In the four years since work began, the DOCSIS 4.0 spec has continued to hum along on a fast track. At CableLabs the DOCSIS 4.0 working groups have focused on refining the spec to make it more powerful and efficient. In industry labs silicon providers have worked on designing and developing the chipsets to support DOCSIS 4.0 passives, actives, cable modems, and DAA equipment.
At the same time, several cable operators have begun planning for upgrading their outside plant for DOCSIS 4.0 by expanding the spectral capacity, clearing their existing spectrum, and carrying out other necessary changes.
During this activity, CableLabs has begun staging equipment interoperability tests to see how well they perform and operate together. For 2022 CableLabs and Kyrio have more than a dozen interops scheduled. At the first FMA interop there were five vendors participating with a few operators in attendance. We expect to see more in future interops, both for FMA and DOCSIS 4.0.
There are many reasons why cable technologists have brought DOCSIS 4.0 to market in such record time. The ability to fulfill the 10G vision is just one of them. Despite the new spec’s great promise, DOCSIS 4.0 will not exactly be a “walk in the park” for cable operators to deploy and manage. Indeed, the new spec poses a few daunting technical, operational, and business hurdles for cable providers to overcome. Specifically, compared to earlier versions of DOCSIS, DOCSIS 4.0 makes one of the most dramatic changes to the physical layer so far and adds more features than any of its predecessors.
But with trials and tribulations come the opportunity to make significant advancements in modernizing the cable network.
First and perhaps foremost, cable operators must clear enough capacity in their systems to take advantage of the large blocks of spectrum that DOCSIS 4.0 makes available. That can be a tall order for the industry’s standard 750 MHz, 860 MHz, or even 1 GHz systems with digital video channels, scores of HD video channels, dozens of bonded broadband channels, IP video services, voice services, business services, and the like. For operators, it means taking steps like switching over to all-digital transmission, eliminating analog video channels, upgrading from MPEG-2 to MPEG-4 for HD video to make more efficient use of their current spectrum and clear space for DOCSIS 4.0.
Upgrading a cable system to raise the upper limit of its RF spectrum beyond 1 GHz to 1.2 GHz or 1.8 GHz requires new passives and actives. While some of these upgraded devices are available from manufacturers, they must still be purchased and installed on the HFC plant, which takes time. Fortunately, there are creative ways to do this to minimize customer outages.
Light at the end of the tunnel
Cable operators have plenty of reasons for hope as we prepare to face the challenges posed by DOCSIS 4.0 rollouts.
Anticipating a carefully planned incremental rollout strategy, silicon and OEM vendors have designed DOCSIS 4.0 cable modems to be fully hybrid models, capable of supporting both the new spec and the older DOCSIS specs. These new modems can support up to 32 downstream and eight upstream, and up to five OFDM downstream channels and seven OFDMA upstream channels for the DOCSIS 4.0 spec.
As a result, cable operators will be able to leverage these devices for both DOCSIS 3.0 and DOCSIS 3.1 speeds and services without carrying out any immediate plant upgrades. Most notably, they can use DOCSIS 4.0 downstream with DOCSIS 3.0/3.1 upstream, which simplifies the deployment by focusing on the greatest need for more downstream capacity and bandwidth.
No matter where you go, there you are, or at least thereabouts
With the first DOCSIS 4.0 specification being completed and devices now on the horizon for certification by CableLabs, the DOCSIS 4.0 era has clearly begun in earnest. While many, if not most, cable operators do not plan to start deploying the new broadband spec for years, every cable provider undoubtedly has its eyes upon the new multi-gigabit standard as the industry seeks to maintain its competitive edge in the fiercely contested broadband market.
Cable providers face some hurdles in deploying this sixth generation of the industry’s broadband spec. It is not the first time we have met that challenge. Nonetheless many, if not most, of these seemingly daunting challenges can be overcome either in the short-term or over time if the proper steps are taken. Cable operators can take advantage of OFDM availability throughout the spectrum, higher modulation orders and other new technologies, free up more capacity for DOCSIS 4.0 use, increase their plant spectrum limits, seed new cable modems, headend devices, and other new gear, plus make use of new, advanced testing and monitoring products.
So, whether you are planning to start rolling out DOCSIS 4.0 right away or later, cable providers can sort through these issues now, so we don’t get surprised. In an age of gigabit services, the world is moving faster and faster every day. That is why it is critical to start learning and re-learning the technology today.
And never forget that cable not only has a long life, but a long, useful life. And DOCSIS 4.0 is proof of that.
Jeff Finkelstein
Executive Director of Advanced Technology
Cox Communications
Jeff.Finkelstein@cox.com
Jeff Finkelstein is the Executive Director of Advanced Technology at Cox Communications in Atlanta, Georgia. He has been a key contributor to the engineering organization at Cox since 2002, and led the team responsible for the deployment of DOCSIS® technologies, from DOCSIS 1.0 to DOCSIS 3.0. He was the initial innovator of advanced technologies including Proactive Network Maintenance, Active Queue Management and DOCSIS 3.1. His current responsibilities include defining the future cable network vision and teaching innovation at Cox. Jeff has over 43 patents issued or pending. His hobbies include Irish Traditional Music and stand-up comedy.
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