The Questions Vecima Gets Asked Most Often About DAA And FTTH: “How are Cable Operators Handling Video in Their Distributed Access Architecture (DAA) Deployments?”  


Published by Colin Howlett, Vecima Chief Technology Officer 

Published by Jeff White, Vecima Advisor

How to handle video is one of the most common questions we get here at Vecima when operators are looking at deploying DAA.

 Option 1 – IP Video

Ideally, given that moving to DAA provides for an increase in capacity through better signal quality, the DAA transition is an opportunity to use that bandwidth to implement an IP video solution. An all-IP video environment reduces power costs, reduces headend space associated with QAM supporting systems, and helps lower real estate costs. If you are planning to move to IP video in parallel with DAA, Vecima can help with our industry leading MediaScaleX  solutions.

For cable operators who do not have the luxury to migrate to IP video in parallel with DAA, there are several different options for implementing QAM video in a DAA environment. As illustrated in the figure below, the same methods work for both Remote PHY (R-PHY) and Remote MACPHY (R-MACPHY) deployments.

Option 2 – Existing QAMs

When a cable operator is using a large bank of edge QAMs, and not their CCAP, to deliver video, they can insert a Video Engine and continue using the edge QAMs that are already in place. A Video Engine is a small box that receives RF from the edge QAM, demodulates it, and pushes the Multiple Program Transport Stream (MPTS) over the Ethernet fiber network using Downstream External PHY Interface (DEPI) multicast. The DAA node receives the MPTS, remodulates the QAM channel, and transmits that RF over the cable plant to the set-top box. This approach allows operators to keep video out of the CCAPs, or avoid the work of integrating the CCAP, knowing they are going to eventually migrate to IP delivered video over a DAA network.


QAM Video implementation options in DAA

Option 3 – Existing iCCAP

The second option is suited for operators who have moved to a fully integrated – data and video – CCAP chassis to simplify their hub environments. In this situation, it is easy to transition the integrated CCAP to a Remote PHY CCAP-core that sends video as DEPI.

Remote MACPHY requires a bit more effort, but also pays bigger dividends. In R-MACPHY deployments, many operators are leveraging their CCAP devices as Video Cores. Since R-MACPHY handles the DOCSIS part of the equation, the entire capacity of the CCAP device is made available to deliver QAM video. This option is also great for operators migrating from R-PHY to R-MACPHY, where they can leave the QAM video in place until they complete the transition of installed consumer devices to all-IP video delivery.

Option 4 – Video Core Appliance

Another option is to use a Video Core Appliance. A DAA deployment uses a split edge QAM architecture with QAM generation at the edge. A full QAM channel is sent over a multicast tunnel using DEPI. All the other edge QAM functions – multiplexing, inserting private data, PID remapping, and correction – are kept centralized in the Video Core appliance. It is like a typical video QAM, taking in IP, but instead of transmitting RF, it transmits DEPI. The DEPI feed works equally well for R-PHY and R-MACPHY, and it supports all kinds of broadcast scenarios. The Video Core Appliance reduces the space and power requirement in the hub. This option is well suited to operators using flexible “headend-in-a-box” chassis (especially in DVB video markets) where an existing chassis may be able to add a card or software license to support DEPI output directly.

Option 5 – Virtual Video Core

Finally, an operator can use a Virtual Video Core, which is a software version of a Video Core Appliance. As a result, it has all the advantages of the appliance, plus it is even more efficient from a space and power standpoint. So, the existing edge QAMs become a virtual implementation on a commercial off-the-shelf server. This perfectly aligns with the increasingly software-only video backend infrastructure and leverages the IP Content Delivery Network (CDN). Once the video is being delivered with a software-based solution, operators can move it deeper into the network – to the data center. So, with DOCSIS and modulation pushed to the node and video centralized to the data center, hubs and headends can be dramatically reduced or simplified.

It is useful to note that these options can be mixed and matched for broadcast and narrowcast video. For instance, a video engine could be used to deliver broadcast videos, and a Virtual Video Core could deliver the narrowcast.

To learn more about Vecima’s solution for managing QAM video in a DAA environment, visit us at  

This blog is the one in a series of blogs from Vecima Networks looking at the most-asked questions we get regarding DAA and FTTH.  Here are the previous questions in the series:

Vecima is always interested in hearing from you. Please e-mail David Slovensky, Vecima Marketing Content Manager at if you have questions, comments, or ideas for future blog topics.