DENVER — Nokia is showing off its Distributed Access Architecture (DAA) at this week’s SCTE-ISBE Cable-Tec Expo. The virtualized solution gives cable operators the flexibility to deploy both remote PHY (R-PHY) and remote MACPHY (R-MACPHY) devices within the same network and switch from one to the other.
Nokia’s DAA moves cable access layer functions that are traditionally placed in the headend and hub sites to the access nodes. To date, cable operators have had to choose between two DAA approaches: R-PHY, which moves only the DOCSIS signal generation (PHY) to the access node; and R-MACPHY, which moves both the PHY and DOCSIS processing (MAC) to the access node.
Nokia’s DAA technology stems from its acquisition of Gainspeed in 2016.
Jeff White, Nokia’s head of cable strategy and business development, was one of the founders of Gainspeed. He said, “We need to push Ethernet and IP deep into the network and make headends look more like data centers. We push the PHY and MAC into the outside plant.”
Dispensing with CCAP
While this week’s cable show has plenty of talks about the converged cable access platform (CCAP), Nokia’s DAA strategy bypasses CCAP, entirely.
CCAPs replace the old cable modem termination systems (CMTSs) and put ports for both data and cable video on a single device. It promises to simplify the network and save space, power, and cooling at cable headends.
But White said the CCAP still requires about the same amount of space and power in headends as the CMTS. He posits that the big CCAP vendors — Cisco, Arris, and Casa — don’t want to lose that lucrative business, so they’re arguing that only the PHY should be pushed to the outside plant and the MAC should remain at the headends.
White said, “New vendors like Nokia and Huawei and Vecima say: ‘We don’t need to protect that CCAP box. We think it’s more efficient to push all DOCSIS functionality into the plant.’”
With Nokia’s DAA, there is no need for a CCAP box at the headend. Nokia pushes the MAC and PHY to the edge of the network and manages them from a controller in the headend.
“If you sit at our controller UI and you’re configuring our system, it looks like a CCAP box,” said White. “The remote MACPHY in the plant looks like line cards on a CCAP. It spoofs a CCAP box, making it easy for the operators. You’ve distributed processing and centralized control. The only thing left in the headend is switches, routers, and servers, the same stuff used in data centers.”
Nokia’s solution does give flexibility, though. It enables operators to deploy R-PHY, R-MACPHY, or a combination of both. “We’re big proponents of MACPHY,” said White. “We think in most environments it makes the most sense. There are situations though where customers want to use remote PHY and not remote MACPHY.”
The broadband provider WOW is deploying Nokia’s virtualized Distributed Access Architecture (vDAA), including the Gainspeed controller, Gainspeed access node, and Gainspeed video engine. Once fully deployed, WOW will be able to effectively eliminate the CMTS/CCAP as a physical box and replace its analog optical transmission with 10Gbps Ethernet.
However, White said WOW is taking a “cap-and-grow approach.” It’s leaving its existing CCAPs in place for the time being and deploying the Gainspeed technology for new nodes.