Flexible MAC Architecture (FMA) Phase 1, the R-MACPHY portion, was issued in September of 2020. This means that both R-PHY and R-MACPHY are now specified in CableLabs!

Why does it matter?

• MSOs can confidently deploy Distributed Access Architectures (DAA), R-PHY and/or R-MACPHY,in their networks today
• Since the R-PHY and FMA specs share many attributes (e.g. -the video architecture and interfaces are all the same) it is easy to mix and match R-PHY and R-MACPHY in an MSO network

What exactly is the FMA specification?

It is a series of four specifications:

• FMA-SYS – System level architecture and requirements
• FMA-MMI – Interface between MAC Manager and R-MACPHY Device (RMD)
• FMA-PAI – Interface between PacketCable Aggregator and RMD
• FMA-OSSI – Modifications to CCAP-OSSI to handle FMA for OSS integration

Along with these specs are two sets of object models delivered just like open source code:

• YANG models for FMA-MMI
• Google Protocol Buffers (protobuf) API for FMA-PAI

These machine-readable models ensure interoperability between vendors and streamline bug fixes, providing a major improvement over previous CableLabs specification and interoperability efforts which did not have support of modern tools and automation.

What is the exact status?

CableLabs has issued (i.e. made publiclyavailable and implementable) FMA-SYS, FMA-MMI, and FMA-PAI.FMA-OSSI will lag these specs by about six to nine months, which is typical since the OSSI work always comes available last in any DOCSIS specification effort.

How has Vecima been involved?

Vecima has been a strong CableLabs supporter for many years and has championed interoperability as shown with our market-leading interoperable R-PHY nodes and video and monitoring solutions. We have a strong belief in the technical underpinnings and the unique environment that CableLabs has facilitated in the industry.

Key contributors to thebody of FMA specifications from Vecima have been Doug Johnson and RexColdren. They were instrumental in propagating thearchitectural vision of work originated by both Vecima and Gainspeed as the original creators of R-MACPHY. Doug and Rex made many of the key architectural proposals and wrote significant portions of FMA-SYS. Doug was primary author of FMA-MMI and the associated YANG models for FMA-MMI. He has led Task Force 1 (MMI) from the start and has also been active in Task Force 3 (OSSI) and Task Force 4 (Data Forwarding). Rex, joining Vecima from the recent Nokia/Gainspeed acquisition, was primary author of FMA-PAI and the associated protobuf API for FMA-PAI. He has led Task Force 2 (PacketCable/Lawful Intercept) and has been a key contributor in Task Force 3 and Task Force 5 (PNM).

Were other vendors and MSOs involved?

Yes, many large MSOs (CableLabs members) have been active on the committee, including Cox, Charter, nbn, LGI, Vodafone, and others. All vendors in the DAA vendor community also participated.Leadership was provided by a unique CableLabs/vendor/operator chairmanship, including:

• Jon Schnoor at CableLabs with the CableLabs chair and oversight position.
• Mike Emmendorfer at Commscope as the vendor chair.
• Jeff Finkelstein at Cox as the MSO chair.

Will Vecima support FMA?

Absolutely! Vecima is committed to standardization and interoperability of DAA technologies. The Vecima R-MACPHY product, which is already deployed with multiple operators all over the world, served as the architectural model and guiding light for FMA specification. It is software upgradable to be fully compliant to the FMA specifications, which have introduced new ideas and approaches on top of the existing deployed product. These upgrades are in progress in current product and FMA will be supported in future product as well.

What is next for FMA?

The FMA Working Group is now working with CableLabs on an Interop Event schedule to ensure the specifications have all they need to ensure interoperable implementations amongst vendors. Expect updates to the specifications out of the Interop Events and operational improvements as operators deploy R-MACPHY at scale.

Published by Colin Howlett, Chief Technology Officer at Vecima Networks

Published by Jeff White, Senior Vice President of Cable Strategy at Vecima Networks