The Big Cable DAA Update

Ahead of SCTE, we look at cable's ongoing efforts to shift to a distributed architecture. Is 2018 the year that DAA deployments take off?

Mari Silbey, Senior Editor, Cable/Video

October 11, 2017

11 Min Read
The Big Cable DAA Update

With SCTE Cable-Tec Expo less than a week away, the time is right for a review of how distributed access architectures (DAA) have advanced in the last year. There are several reasons this is so important. First, there's consensus in the industry that the move to distributed architectures is part of a once-in-a-lifetime, generational shift in the cable access network. Second, the new technology is bringing with it new competitors to the cable market. And third, the way the DAA revolution plays out will have a significant impact on how broadband is delivered in the future, part of a trend toward far greater network virtualization, automation and the drive to move many resources closer to the network edge.

So what's happened in a year? Quite a bit, but that doesn't mean there aren't still kinks to be worked out. On the one hand, CableLabs is already up to its eighth version of the Remote PHY specification, which is one of the main ways DAA will be implemented. CableLabs has also just launched a qualification program for testing Remote PHY devices. That means the spec is reaching a critical state of maturity, enabling operators to consider deploying Remote PHY technology at scale.

On the other hand, 2017 hasn't turned into a year of DAA deployments. If anything, cable operators are moving forward a little more slowly than expected, taking their time to ensure that all of the pieces fit together and that new technologies cooperate with existing back-office systems. There have been early trials this year, but vendors agree that 2018 will actually be the year that commercial deployments take off.

The advantages of DAA include digitizing the link between headend/hub and the cable node to improve signal quality and network management capabilities, as well as reducing the number of specialized hardware chassis (CMTS or CCAP) needed in cable headends and hub sites as bandwidth demands continue to grow. Cable operators won't roll out DAA upgrades everywhere at once, but many will deploy Remote PHY or Remote MAC/PHY devices as they split nodes to decrease the number of subscribers in different service groups. Many operators will also do it when there's an opportunity to get rid of a hub site altogether in favor of deploying more, and more intelligent, nodes. (See In Cable First, WOW Distributes & Virtualizes the Access Network.)

Figure 1: CableLabs diagram of a high-level Remote PHY architecture CableLabs diagram of a high-level Remote PHY architecture

Deployments won't necessarily be easy. One of the biggest challenges with DAA technology today is interoperability. Vendors universally express their support for new optical nodes that are interoperable with CCAP cores from a variety of other manufacturers, and vice versa. However, interoperability is still largely an aspiration today. CableLabs said in a blog post just last week that "interoperable Remote PHY devices (RPDs) now exist and will be available on the market soon." Yet nearly every single DAA vendor that Light Reading has spoken with has been much more cautious in their assessment of the current interoperability situation.

Rei Brockett, a Remote PHY project manager for Arris Group Inc. (Nasdaq: ARRS), for example, says, "For the operators who are looking to do a mixed vendor solution, there's a little bit more of the manual [process] in the sense that they need to check with both of their vendors to make sure that what they want is supported well."

And Nokia Corp. (NYSE: NOK)'s head of cable business strategy, Jeff White, says, "I would be surprised actually if anyone is interoperable yet. I think if we take a snapshot a year from now or 18 months from now, that will be very different."

There's also a challenge of scale with the new optical nodes that operators plan to deploy as part of their deep fiber and distributed access architecture initiatives. Brockett talks about ambitious service providers planning to add thousands of new optical nodes per month. Indeed, Comcast Corp. (Nasdaq: CMCSA, CMCSK) has already said it wants to deploy 1 million new nodes over the next several years, while Cox Communications Inc. plans to increase its node volume by 8x in the same time frame. But field work means construction and labor, which often introduces unexpected costs and delays into the process. (See Big Year Ahead for Cable Network Capex .)

As for the DAA vendors, they're anxious to move forward. The incumbents in cable access technology like Arris and Cisco want to secure their hold on the market, while those companies with new network approaches like Harmonic Inc. (Nasdaq: HLIT) and Nokia want to prove their mettle. Here's a look at some of the top contenders across the DAA vendor landscape, from Arris and Cisco Systems Inc. (Nasdaq: CSCO), to Harmonic and Nokia, to Casa Systems Inc. and Huawei Technologies Co. Ltd. , all of whom will likely have new demos to share at SCTE Cable-Tec Expo in Denver next week.

Next page: A look at Arris

In the DAA space, Arris is delivering Remote PHY devices first, but has also said it will sell Remote MAC/PHY solutions as needed. According to Brockett, Arris has two optical nodes initially designed for Remote PHY deployments. They include multiple slots for modular additions, which in turn can accommodate a traditional hybrid fiber-coaxial network configuration, a PON extension or a Remote PHY module. Operators can buy these nodes with a Remote PHY module embedded, but they can also order R-PHY modules that are then retrofitted into existing compatible nodes already in the field.

Arris was first to market earlier this year with the announcement of a Remote PHY deployment with Danish service provider Stofa. However, Brockett describes that implementation as a learning experience, with Arris working to understand any bugs in the system and to make the solution more user-friendly. Even with this early deployment, Brockett is talking about 2017 as a trial year for the technology. General availability of Arris R-PHY products will come in 2018. (See Arris Wins Remote PHY Deal With Stofa.)

Cisco is firmly rooted in the Remote PHY camp in the debate over whether operators should push only the PHY layer from the CCAP down to the node, or whether they should move both the MAC and PHY layers. Some operators are more comfortable with this approach because it feels like a stepping stone on the path to virtualizing the entire CCAP chassis. However, Cisco also has a vested interest (as does Arris) in preserving dedicated CCAP hardware because it makes money from those products. (See The Cable DAA Vendor Race Begins.)

While Cisco would like to maintain and grow its share of the cable access market, the company also knows that its customers will only accept solutions going forward that are interoperable among vendors so that they have choices in the buying process. Recognizing that fact, Cisco has been very aggressive in pushing OpenRPD, a project to ensure R-PHY devices (RPDs) and CCAP core devices made by different vendors can work together.

"Interoperability is really fundamental to us," says Sean Welch, Cisco's VP and GM of service provider infrastructure.

For more cable market coverage and insights, check out our dedicated cable content channel here on Light Reading.

At a conference in May, Cisco announced specific Remote PHY interop testing with other OpenRPD vendors, including VECTOR Technologies, BKtel networks and Teleste Corp. (See Cisco Debuts Remote PHY Solution.)

As for Cisco's own RPD, the company has designed a Remote PHY solution that's embedded solely within its own optical node. However, Welch points out that Cisco's nodes are modular in nature, which means they could theoretically be fitted with another company's R-PHY module in the future.

Nokia entered the cable DAA market by way of its acquisition of Gainspeed in 2016. Gainspeed had been a proponent of a Remote MAC/PHY solution over an R-PHY approach. However, the company (now part of Nokia) has just announced a new solution that allows operators to deploy a cable access node that can act as either a Remote PHY product or as a Remote MAC/PHY solution. The trick here is that Nokia has virtualized the DOCSIS MAC layer as its own virtual network function (VNF). That VNF can run either in the node in a Remote MAC/PHY deployment, or it can run in an off-the-shelf server in a headend, hub site or data center. (See Nokia Debuts First Fully Virtualized Cable Access Architecture.)

Nokia's White describes the Gainspeed node as a universal device where converting from Remote PHY to Remote MAC/PHY is "no different than adding DOCSIS channels" to a CCAP chassis. Each node looks like a CCAP line card to the Gainspeed access controller, and everything is managed in software.

The Nokia solution is revolutionary compared to what traditional CCAP vendors are offering, and the company can now point to an early customer deployment for the first time. With its announcement of WOW as a DAA customer yesterday, Nokia gains significant credibility both in its approach to CCAP virtualization and as a competitive vendor in the cable access space.

WideOpenWest Holdings LLC (WOW) COO Cash Hagen says that moving forward, his company will deploy the new Nokia/Gainspeed nodes in many of the locations where it needs to make node splits. (See In Cable First, WOW Distributes & Virtualizes the Access Network.)

Next page: Harmonic touts CableOS commitments

Like Nokia, Harmonic is in a position where it isn't trying to preserve a major share of CCAP business as it helps to transition operators toward distributed access architectures. The company jumped out of the gate last year with a fully virtualized CCAP core solution called CableOS, and now it also has an optical node product called the Ripple and a Remote PHY module called the Pebble. (See How Harmonic Aims to Disrupt CCAP Market.)

"We have a clean slate with a fresh and modern node design. There are a lot of things that might not be obvious but we believe are unique and valuable in the modern node design versus extending the life in aging legacy nodes," says Asaf Matatyaou, VP of the cable edge business at Harmonic.

Harmonic's Pebble will also fit into node hardware from other vendors, which Matatyaou points out can be important given that operators may need different node form factors and may have different power constraints to work with.

Harmonic hasn't given many specifics about CableOS and Remote PHY deployments, but Comcast is a known CableOS customer and Matatyaou says Harmonic has Remote PHY customer commitments already both in the US and elsewhere. Like his peers at other companies, Matatyaou also believes there will be a major Remote PHY ramp-up in 2018.

Casa is an interesting case as a DAA vendor because while it is a very successful CCAP manufacturer, it also isn't the giant that Cisco and Arris have been in the broader cable industry. Casa also brings experience with it from the wireless sector where it's already developed the Axyom software architecture for supporting its own virtualized cellular and WiFi products. Casa's virtual CCAP also fits into the Axyom ecosystem, and the company will once again be showing how that works at this year's Cable Tec-Expo. (See Casa Joins Virtual CCAP Parade.)

Casa's Remote PHY solution is a module that can be embedded in its own node or, at least theoretically, in those from other companies. Casa's large-format node can support either one or two R-PHY modules, depending on a customer's needs. A new line card in Casa's CCAP chassis aggregates and controls its Remote PHY nodes.

As for the operators that might want a Remote MAC/PHY solution, Casa's senior director of cable products, Jeff Leung, says, "Casa technology is flexible enough that we could do MAC/PHY as well."

Huawei is a bit of a puzzle in the cable DAA space, not because it hasn't been aggressively marketing its own Remote MAC/PHY solution, but because it still doesn't seem to be gaining any traction in the lucrative US market. This is likely largely a political issue, as the US government doesn't want Huawei equipment embedded in the country's critical infrastructure, but it's one that the company has long thought it would be able to overcome.

Heading into Cable Tec-Expo 2017, there are still no signs that Huawei has made any progress. And yet, it never pays to count Huawei out of a fight.

Stay tuned?

Tying it all together
Ultimately the move toward DAA technology is only one piece of the effort to virtualize the cable access network. In the not-too-distant future, the cable conversation will shift more significantly to talking about broader software control and so-called "cloud native" systems.

In the meantime, this year's Cable Tec-Expo will unveil the latest in cable distributed access developments and offer a prelude to 2018 -- the year forecast to be the start of major DAA deployments.

— Mari Silbey, Senior Editor, Cable/Video, Light Reading

About the Author(s)

Mari Silbey

Senior Editor, Cable/Video

Mari Silbey is a senior editor covering broadband infrastructure, video delivery, smart cities and all things cable. Previously, she worked independently for nearly a decade, contributing to trade publications, authoring custom research reports and consulting for a variety of corporate and association clients. Among her storied (and sometimes dubious) achievements, Mari launched the corporate blog for Motorola's Home division way back in 2007, ran a content development program for Limelight Networks and did her best to entertain the video nerd masses as a long-time columnist for the media blog Zatz Not Funny. She is based in Washington, D.C.

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