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21 November 2019

Never underestimate the video guys when deploying DAA

If one message was clear from Cable Congress 2019, it was not to misjudge the value of video technology teams in the deployment of network access equipment.

“If you are an operator, please, please take the video guys onboard,” implored a panel discussing broadband distributed access architectures (DAA) in Berlin last week. Representatives from operators well-versed in DOCSIS 3.1, Remote-PHY and MAC-PHY (media access control and physical network layer) deployments, including Vodafone and Tele2, were joined by vendors Teleste and Ciena in echoing this message. Although, as a separate DAA story in this week’s issue underscores, agreement was not guaranteed.

Typically, according to the panelists, video engineering teams come into the picture way too late in the DAA rollout process and as a result can cause problems further down the line.

“You need to have the DOCSIS guys, the HFC guys, the ethernet guys, the IP routing guys and – crucially – the video guys all in the same room. Building cross-functional teams is essential,” came one declaration. This is really an old story in a new setting, as early IT settings demonstrated how much time was wasted having ops and programming separated.

Centralizing and virtualizing components of the network headend brings major benefits but isn’t without its difficulties when video is an afterthought. For example, upgrading the cable modem termination system (CMTS) at the headend using distributed converged cable access platform (CCAP) technology means unifying all routing, switching and QAM functions to send video and data from a single device.

Distributed CCAP, a subset of DAA, enables the migration of the PHY and MAC layers – separately or together – from the headend to an access optical node (or so-called “intelligent” node) where functions are combined. This joining of functions between the CMTS, physical layer and dense video edge QAM modulator means the CCAP can handle IP video before RF conversion for transport over the access network.

This brings massive efficiency and QoS gains but the consensus from DAA experts at Cable Congress is that video engineering teams need to be included in plans even before deploying a distributed CCAP.

Monstrous demand for IP video coupled with mass reliability on traditional QAM video delivery is the issue being addressed by DAA, which in turn falls to the network’s Video Core. This is where encryption, multiplexing, modulation and bandwidth optimization techniques take place before video is delivered over the access network. Virtualizing the traditional video core unifies MPEG-2 and IP/ABR video to support DAA – converging the video backbone to support existing QAM-based CPE and IP devices.

Conclusively, there is no such thing as too early for video input where DAA deployment is concerned.