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The Advantage of Remote PHY

- October 13, 2017 - 0 Comments

An Analysis of Remote PHY vs Analogue Deep Fiber Total Cost of Ownership

In a recently published white paper, The TCO Advantage of Remote PHY, we compare the CAPEX and OPEX of a Remote PHY deployment with an Integrated CCAP/HFC deployment. A next-generation Distributed Access Architecture (DAA), Remote PHY moves access hardware from the headend to smaller hub sites or into the plant, providing cable operators with a number of benefits including a reduced footprint, lower operational costs and bandwidth growth.

Although several options exist for deploying a DAA, the majority of cable industry equipment vendors are aligned with Remote PHY. It is the only DAA standard in the industry; the result of an industry-wide initiative, OpenRPD, chaired by CableLabs® with substantial contributions to the specification from Cisco. It is also the only DAA architecture that supports next-generation technologies such as Full Duplex DOCSIS 3.1 and Cloud Native virtualization. As a market enabler, the Remote PHY standard ensures product development is open and accessible to all equipment vendors. And most importantly, cable operators can select a standardized Remote PHY device (RPD) that best meets their needs, without being locked into a single vendor’s proprietary solution.

Remote PHY vs. the Status Quo

Why compare a Remote PHY and an Integrated CCAP/HFC deployment? Although Remote PHY offers a number of advantages, it does represent a new deployment model that must be operationalized.  As such, some operators may choose to continue splitting fiber nodes until they ultimately reach the same fiber depth as a Remote PHY Fiber Deep deployment. Theoretically, this approach would offer the same capacity expansion without the challenges of incorporating new technology and adapting to a new operational model.

This approach, which we will call Analog Fiber Deep, is really just continuing down the current path of splitting fiber nodes into new segments and adding corresponding integrated-CCAP capacity in the headends and hubs. Although not as flexible as Remote PHY Fiber Deep, Analog Fiber Deep would enable a fiber deep or node plus zero architecture but with analog modulated optics, i.e. traditional HFC.

The Comparison Model

To accurately compare the OPEX and CAPEX for Remote PHY Fiber Deep and Analog Fiber Deep deployments, we evaluated the costs associated with construction per cable mile, bandwidth per service group, segmentation, CCAP chassis density and scalability, equipment and HVAC powering estimates, headend footprints, and the Remote PHY CIN Network. CAPEX estimates were then developed for both scenarios. CAPEX was estimated based on bandwidth and hardware

CAPEX estimates were then developed for both scenarios. CAPEX was estimated based on bandwidth and hardware scalability and included the cable construction cost estimates.

The Flexibility of Remote PHY

As an inherently flexible platform, Remote PHY supports a number of deployment options that deserve mention.  With considerations such as geographic network distribution, short-term and long-term goals, and anticipated subscriber and bandwidth growth rates, an operator may choose to deploy Remote PHY using:

  • A Remote PHY Shelf. A shelf can contain a few or many Remote PHY Devices (RPDs).  This deployment option allows a hub to contain only RPD shelves, while centralizing the CCAP core.  Shelves can also be used as “port extenders” when paired locally with a CCAP core.
  • A Business as Usual fiber node location. Th
    is deployment uses the existing or traditional fiber node location, typically passing several hundred homes, and incorporates a number of actives or amplifiers in line after the fiber node.  An operator could deploy an RPD in an existing location or as part of a node segmentation effort.
  • A new Fiber Deep node location. Because of its extreme segmentation, this deployment offers the most benefit from Remote PHY as each fiber deep location typically serves 50-70 homes and there are no active components past the RPD/fiber node location. This deployment is also referred to as “node plus zero” meaning zero active components after the fiber node.

A combination of these deployments is possible and even viable in many situations.  For example, an operator could deploy both Business as Usual and Fiber Deep nodes when converting an existing node to Remote PHY.  This type of deployment would enable the operator to roll out Fiber Deep only to the areas that need capacity relief.  Alternatively, an operator could deploy a mixture of Remote PHY shelves and nodes in a given area. Whichever path they choose, the flexibility of the Remote PHY deployment architecture enables operators to directly address capacity needs.


Remote PHY MER benefits; by replacing the Analog RF Optics with Digital Ethernet Optics the network MER improves dramatically as a result of a reduction in RF impairments.  The graph demonstrates the typical improvement that can be accomplished utilizing Remote PHY Nodes.




Advantage: Remote PHY

While the white paper comparison between a Remote PHY Fiber Deep and Analog Fiber Deep deployment is based on a representative but hypothetical hub, both the OPEX and CAPEX data clearly shows the cost-effectiveness and advantages of a Remote PHY Fiber Deep deployment.

Substantial OPEX and CAPEX gains are made based on CCAP chassis density and scalability, equipment and HVAC powering estimates, headend footprints, and the Remote PHY CIN Network. Particular attention should be paid to the Remote PHY Fiber Deep deployment’s reduction in headend footprint requirements, as this can often negate the need for facilities expansion.

The graphs above show the number of racks required in a headend for both architectures based on three phases of Bandwidth service tiers growth and two consecutive Service Group splits. Ultimately the difference between the two architectures is 39 headend racks.

Find Out More

Download a copy of the white paper to read our full analysis of Remote PHY’s TCO benefits, including how a Remote PHY shelf or a Business as Usual fiber node deployment can be used to gain additional savings.

If you’re traveling to the 2017 SCTE-ISBE Cable-Tec Expo this month, make sure you stop by and see us at booth #987 where we will gladly walk you through a demonstration of the Remote PHY technology and explain the benefits in more detail.


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