Under One Roof
Cable's move to unify video architectures may take years to reach the field
by Todd Spangler -- Multichannel News, 1/11/2009 7:00:00 PM
Good things come to those who wait — and wait, and wait.
In a development that promises greater flexibility and simplicity for cable operators deploying switched digital video and other applications, the cable industry has merged two disparate video-services architectures invented by Comcast and Time Warner Cable. But products based on this consensus about how key headend elements communicate could still be years away from seeing action in the field.
In November, CableLabs published specifications defining the way headend equipment delivers switched digital video and video-on-demand services. The specs are designed to let vendors deliver standardized video components, including truly “universal” quadrature amplitude modulation devices that work with data and video applications, in any cable system environment.
| At a Glance |
|---|
| Modular Headend Architecture |
| SOURCE: CableLabs |
| Description: Encompasses existing DOCSIS modular cable modem termination system (M-CMTS) specifications and provides a common approach for accessing and managing universal edge QAMs, video edge QAMs and M-CMTS edge QAMs. |
| What's new: Specs related to video services published in November under the Modular Headend Architecture umbrella synthesize Time Warner Cable's Interactive Services Architecture (ISA) and Comcast's Next Generation on Demand (NGOD). |
| Specification contributors include: Comcast, Time Warner Cable, Cox Communications, Rogers Communications, Shaw Communications, Cable Europe Labs, ETRI, Arris, BigBand Networks, Broadcom, Camiant, Cisco Systems, Harmonic, LiquidxStream Systems, Motorola, RGB Networks, Vecima Networks |
The cable consortium's Modular Headend Architecture includes protocols for cable modem termination systems and video components. Until now, the de facto standards for setting up VOD and switched video sessions and managing resources have been Time Warner Cable's Interactive Services Architecture (ISA) and Comcast's Next Generation on Demand (NGOD).
“Eventually we'll only have to worry about one set of interfaces,” said Greg Hardy, vice president of business development in Cisco's Service Provider Video Technology Group. “The benefit of driving toward this open architecture is one of interoperability, to give the MSO the ability to mix components, and hopefully lower costs.”
Independent suppliers are counting on the specs to open the market to more players.
“This was important for us, because now we can compete not on the fact that we have some proprietary piece but that our edge QAM can do things nothing else on the market can do,” said LiquidxStream Systems vice president of business development Tony Pierson.
But it will probably be at least two years before products that employ the new CableLabs specs are deployed, said Randy Fuller, vice president of business development for Camiant, a provider of network-policy management systems.
“The timing is the $64,000 question,” he said. “Quite frankly, we don't expect the Modular Headend Architecture specs to affect the video business for some time in terms of deployments.”
In a way, the unified video specifications represent a return to square one.
Why? For vendors, they'll now have to develop and support a third architecture — the consolidated CableLabs one, plus the legacy ISA and NGOD versions, said Andy Carroll, product manager in Motorola's switched digital video group.
“In the short term it actually complicates things,” Carroll said. “It takes time to transition to the newer system… I think there's going to be a lot of momentum behind it but you still have the reality of systems out in the field already.”
Cable operators, meanwhile, have already been rolling out ISA or NGOD with universal edge QAMs. Before moving to an architecture based on the unified spec, they will need to test and verify components based on the Modular Headend Architecture in their own networks.
“The idea of deploying yet another architecture inside of two years would be a land-speed record for cable,” Fuller said. “If you could roll back time and start everything with this one architecture, life would be great, but that's not the case.”
For the most part, adapting existing switched video, VOD and edge QAM systems for the CableLabs Modular Headend Architecture should be a matter of software upgrades, according to industry executives. Biren Sood, vice president of marketing and business development for BigBand Networks, noted that his company's switched digital video system already supports ISA and NGOD in the same platform.
“The next major step for us as a company is to support the new protocols,” he said. “I don't want to trivialize it and say it's just a matter of merging code, but it's very achievable.”
Added Cisco's Hardy, “It's really not that big of a change. If you look at CableLabs' technical overview, it's very similar to things we've been working on as an industry for the last several years.”
CableLabs expects to host an interoperability event for equipment based on the video specs, either in the spring or summer of 2009. That should provide a sense of what would be practical to include as part of qualification testing, according to CableLabs chief technology officer Ralph Brown.
But certifying interoperability for video equipment is more challenging than with DOCSIS CMTSs and cable modems, Brown said, because not all parts of the video-delivery chain are standardized.
“When it comes to video, there's a systems-integration exercise depending on whether it's Motorola or Cisco and based on other components of the video architecture,” he said. “We by no means can do all the possible combinations that are in the field. It's difficult for us to do an end-to-end test.”
Even so, having a CableLabs seal of approval as a starting point would be another advantage over the current ISA and NGOD architectures.
“If you were an MSO and you mixed-and-matched your video infrastructure pieces, you would feel much more comfortable if those were qualified [by CableLabs],” Pierson said. “The biggest piece is flexibility down the road.”
The end goal is to be able to share QAMs across CMTS and video platforms, instead of deploying those QAMs in fixed configurations. Today “that's not a big enough bang for the buck to move radically from their current plans,” Fuller said.
And while in the long run having one bank of QAMs would — theoretically — be simpler to manage, cable operators typically have different teams of “data guys” who run the CMTS and “video guys” who handle the TV side of the house.
“If it's one big pool of RF [radio frequency] resources, who gets to decide how the spectrum is allocated?” Fuller said. “There's an organizational change that needs to happen as well.”
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