The Big Cable DAA Update

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.

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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

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Duh! 10/13/2017 | 4:50:38 PM
Re: Parallels to C-RAN HFC is most similar to DAS.
msilbey 10/13/2017 | 4:27:34 PM
Re: Parallels to C-RAN Nokia's Marcus Weldon has talked about where all of the access network technologies are converging. It's a very intereesting space right now.
Sterling Perrin 10/13/2017 | 4:06:28 PM
Re: Parallels to C-RAN After giving it a little more thought - and coffee - I realized that cable and telecom are coming from different directions, at least initially. Cable is moving from central to more distributed (DAA) and mobile is moving from distributed to more central (Centralized RAN). But technology limitations/physics are forcing trade-offs to end up with a "partially" distributed cable access and a "somewhat" centralized RAN. That's where the two architectures are looking most similar.

msilbey 10/13/2017 | 3:59:59 PM
Re: Parallels to C-RAN Sterling- Yes, many similarities in approach. As someone who comes from the cable side of the industry, I've been somewhat amazed over the years at the ways the different technology approaches mimic each other. Not because that doesn't make sense, but because the traditional telecom/wireless and cable worlds were populated by very different people. Interesting to watch it all, slowly, converge.
msilbey 10/13/2017 | 3:57:56 PM
Re: Casa is a new major player Fair enough. Casa is second in CCAP shipments. Ironically, I think of it as an advantage that they don't seem as mired in the old-school cable ways. They've now announced customer trials of their vCCAP solution, and I look forward to hearing those trials turn into commercial deployments. 
Sterling Perrin 10/13/2017 | 10:07:25 AM
Parallels to C-RAN It's interesting how similar the DAA architecture is to what mobile operators are doing with centralized RAN- splitting the processing functions and moving some of them closer to the subscribers. In the case of DAA, the functions move closer to the homes, with the remote PHY. In C-RAN, the functions move to the cell tower, closer to the mobile subscribers.

In both cases, the transmission of RF over fiber seems to be a big part of the challenge. In RAN and C-RAN, it is digitized RF in the form of CPRI. In cable, it looks like they do analog RF over fiber. But both analog an digitized RF appear inefficient for the coming data rates and densities.

I don't have any conclusions, just an observation of the similar problems and approaches.

Hardware22579 10/12/2017 | 4:18:51 PM
Casa is a new major player These light reading articles continue to be Arris and Cisco centric, discounting Casa as a major player. Casa has moved into second place behind Arris in deployments of CCAP boxes, so please don't discount them as just another vendor trying to break into the market.  Casa is now an incumbant as much as Arris or Cisco.