The Society of Cable Telecommunications Engineers (SCTE) has kicked off a project to create a new standard for "smart" amplifiers and the use of a common communications protocol for standalone amps, as well as those being built into nodes.

The project, started last month, is forming as cable operators start to move ahead with upgrades of their hybrid fiber/coax (HFC) architectures that consider new 1.2GHz and 1.8GHz amps for future DOCSIS 4.0 networks. Cable operators are expected to swap out a multitude of amps during their transition to DOCSIS 4.0.

Doug Jones, principal architect at CableLabs and a DOCSIS pioneer in his own right, is chairing the new standards group.

Figure 1: The new standard will apply to standalone amps as well as to amps build into a node. That work will also apply to a new breed of standardized GAP nodes that will support an array of service modules.
Pictured is a diagram of a GAP node base.
Click here for a larger version of this image.
(Source: SCTE)

Enhancing the capabilities of this new wave of amps will add another layer of monitoring and communications to the cable plant. And the use of standards will help to ensure that this capability does not give way to proprietary systems and technologies that might end up being incompatible with each other.

"Some operators have a desire to add communications to their amplifiers and some vendors are already making it," Dean Stoneback, senior director of engineering and standards at SCTE, said. "There's pretty much universal agreement that there should be one standard on the protocol."

Using YANG

The focus is on the YANG modeling language for communications, with the general intention to house monitoring and control communications with an amplifier, and to make that capability accessible via the HFC control plane or locally through a direct wired or wireless connection.

CableLabs, which merged with SCTE in January 2020, has already been applying YANG models to DOCSIS 4.0 and the new Flexible MAC Architecture (FMA).

"It's a logical extension to use all of the same modeling principles for talking to the amplifiers," Stoneback said.

In addition to supporting standalone amps and amps baked into nodes, the resulting standard will apply to both flavors of DOCSIS 4.0: Full Duplex DOCSIS (FDX) and Extended Spectrum DOCSIS (ESD), also known as Frequency Division Duplex (FDD).

That work will apply to nodes based on SCTE's new Generic Access Platform (GAP) standards that will support a wide range of snap-in service modules. The GAP standards specify the interfaces in and out of the modules contained inside the GAP node, not what to say to a module. The new YANG model will be used to cover that communications gap, Stoneback said.

Ties to 1.8GHz

Stoneback said the smart amplifier standards project spawned out of the SCTE's work on 1.8GHz amplifier standards, which is nearing completion. Engineers, he added, thought the communications piece would be better served as a separate project involving people more attuned to communications protocols than they are with RF technologies.

Stoneback expects SCTE to complete the first smart amp standards within a year.

If all goes to plan, the standard will provide another layer of communications, management and monitoring capability on the cable network. It will effectively enhance existing Proactive Network Maintenance (PNM) capabilities that support maintenance by monitoring the end points of the network, such as DOCSIS cable modems or gateways.

Stoneback notes that some early use of smart amps is underway in Europe. However, some operators have previously questioned whether the addition of the communications element in the amp justified the costs. It appears that there's enough interest now to spark a standard, at least.

Service providers are asking for the feature, but there's still no telling if they'll end up paying for it. But if they do, the standards will ensure that they're all doing it the same way, Stoneback said.

Update: According to SCTE, here are the active participants in the smart amplifier standards project:

Service providers:

Equipment suppliers and general interest:

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— Jeff Baumgartner, Senior Editor, Light Reading