Technology Concepts in 80 Words: DAA and Remote PHY

Today the industry is shifting to Distributed Access Architecture (DAA), decentralizing and virtualizing headend and network functions. In this edition, we have gathered basic technical definitions around DAA and Remote PHY solutions. The challenge is to not get lost between the acronyms!

In the third part of Intraway’s technology concepts series, we have gathered basic technical definitions of networking. Check out our list of technology concepts related to networking on our blog post.

DAA

Distributed Access Architecture enables the evolution of cable networks by decentralizing and virtualizing headend and network functions. Reduces CAPEX required for fiber construction and OPEX related to space and power. Giving Convergence in Cable Remote PHY and Virtual CCAP Benefits.

CCAP

The Converged Cable Access Platform is a CableLabs-led effort that brings technical and operational unity to two projects: The Converged  Multiservice Access Platform (CMAP), headed up by Comcast Corp. and Converged Edge Services Access Router (CESAR), headed up by Time Warner Cable Inc. (NYSE: TWC). Its goal is to develop a super-dense, power- and space-saving architecture that combines edge QAM and cable modem termination system (CMTS) functions and puts the cable on a path toward service convergence and an IP video platform.

Control Plane

The control plane is the part of a network that carries signaling traffic and is responsible for routing. Control packets originate from or are destined for a router. The control plane, the data plane, and the management plane are the three basic components of a telecommunications architecture. The control plane and management plane serve the Data plane.

Data Plane

It bears the traffic that the network needs to carry. The data plane (sometimes known as the user plane, forwarding plane, carrier plane or bearer plane) is the part of a network that carries user traffic. It defines the part of the router architecture that decides what to do with packets arriving on an inbound interface. Most commonly, it refers to a table in which the router looks up the destination address of the incoming packet and retrieves the information necessary to determine the path from the receiving element, through the internal forwarding fabric of the router, and to the proper outgoing interface(s).

Management Plane

It carries administrative traffic, and it is considered a subset of the control plane.

RPD (Remote PHY Device)

The RPD platform is a physical layer converter, whose functions are:

      • To convert downstream DOCSIS, MPEG video and OOB signals received from a CCAP Core over a digital medium such as Ethernet or PON to analog for transmission over RF or linear optics.
      • To convert upstream DOCSIS, and OOB signals received from an analog medium such as RF or linear optics to digital for transmission over Ethernet or PON to a CCAP Core

N+0 RPD Node

Also known as a “fiber deep” RPD,  it feeds a passive coaxial plant serving area without the use of any active amplification.

N+X RPD Node

It is an RPD that feeds a coaxial plant serving area that has not yet been converted to “fiber-deep” and thus requires some cascade of amplifiers for RF signals to reach customers.

DEPI

Downstream External PHY Interface (DEPI) is the downstream interface between the CCAP Core and the RPD. R-DEPI is based on DEPI. More specifically, it is an IP pseudowire between the MAC and PHY in an MHAv2 system that contains both a data path for DOCSIS frames, video packets, and OOB packets, as well as a control path for setting up, maintaining, and tearing down sessions.

UEPI

Upstream External PHY Interface (UEPI) is the upstream interface between the RPD and the CCAP Core. Like DEPI, it is an IP pseudowire between the PHY and MAC in an MHAv2 system that contains both a data path for DOCSIS frames, and a control path for setting up, maintaining, and tearing down sessions

Narrowcasting

Opposite to broadcasting (retransmission), it is a transmit possibility of publicity or specific information to different segments differed by value, preferences or demographic attributes. 

Switched Digital Video (SDV)

A more efficient way to add new channels and services on existing bandwidth by having digitally encrypted channels switch out when no one’s watching them and switch in when they’re needed. The unwatched channels aren’t transmitted (switched out) until you tune to a new channel.

In the third part of Intraway’s technology concepts series, we have gathered basic technical definitions of networking. Check out our list of technology concepts related to networking on our blog post.

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