Cable operators are doing a variety of things to evolve their networks. One thing they’re doing is transitioning from cable modem termination systems (CMTS) for data to converged cable access plant (CCAP) devices. Cable companies deliver both data and cable video, and the new CCAP hardware puts ports for both technologies on a single device. It promises to simplify the network and save space, power, and cooling at cable headends.
In addition to transitioning to CCAP, cable operators are also working to virtualize the CMTS and/or the CCAP in their headends.
Gainspeed’s technology takes a different tack to virtualize the CCAP.
It separates two layers of control within the cable network: the physical layer (PHY) and the media access control (MAC) layer. The PHY and MAC are loosely analogous to the control and data plane within software-defined networks (SDN). But the cable plant is complex, so it’s not an apples-to-apples comparison. The MAC layer pertains to cable’s delivery of Internet over their hybrid fiber coax (HFC) cables using the DOCSIS protocol.
By separating the PHY and MAC, the Gainspeed technology is then able to move MAC functionality out of the headend and closer to customers at the edge of the network. In addition to saving space, power, and cooling in the headend, moving functionality closer to customers helps cable deal with explosive traffic on the access side.
Jay Fausch, head of cable strategy and business development at Nokia, said Gainspeed uses a remote node composed of hardware and software. “It’s a physical device roughly the size of a microwave,” said Fausch. “It can be in a remote cabinet or strand-mounted, hanging on the wires.”
The device interfaces to both HFC cables and also to fiber lines. It lets cable operators move a lot of processing power out of their headends, and they can still use their existing HFC connections.
“With Gainspeed, it opens up a whole new world,” said Fausch. “Gainspeed set out to virtualize the CCAP and use a headend in the cloud — an SDN-based controller that talks to various access nodes out there.”
Gainspeed also virtualizes functions in the PHY at the headend. That software can reside on common-off-the-shelf (COTS) hardware.
Nokia’s Competitive Stance
Fausch said Nokia can approach virtualization in the cable network unhindered by any legacy position, unlike other vendors that have long provided CMTS equipment.
“There’s remote PHY by Arris or Cisco because they have a big CCAP business to protect,” said Fausch. “Nokia does not. We’re not out to protect an incumbent CMTS position. We can innovate around it in a more elegant way.”
For Nokia, cable companies represent a largely fresh opportunity. Alcatel Lucent, which Nokia purchased in 2016, did bring cable customers to Nokia. Alcatel Lucent provided cable companies with Ethernet Passive Optical Networking (EPON), which uses fiber connections.
Now with Gainspeed, Nokia can help cable companies uses both their HFC connections and their fiber connections to virtualize the CCAP.