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May, 2007

Tandberg, Imagine Put Flesh on Emerging, Modular Cable SDV Standard

Tandberg Television and Imagine Communications have unveiled new switched digital video (SDV) products and an integration pact that promises to bring a modular, multi-vendor cable SDV vision to fruition for cost-effective mass deployments in 2008.

Debuting at The Cable Show '07, May 7-9 in Las Vegas, Tandberg's new OpenStream SDV product suite is designed to provide control and management for large scale, multi-rate (2- to 20-megabit-per-second) video streaming with scalability and redundancy features, including seamless failover.

Answering operator calls for multi-vendor integration, Tandberg, part of the Ericsson Group, and Imagine also have agreed to pre-integrate OpenStream SDV with Imagine's Quality On Demand Product Suite (QOD Product Suite) which features a Variable Bit Rate and statistical multiplexing technology (VBR/StatMux) solution unique among cable suppliers.

"We've been working with operators for over a year on this," says Michael Adams, vice president of system architecture for Tandberg. "The last part of 2007 is probably going to be trials, and in 2008 we see operators saying, 'Now we've sorted out the operational aspects, how it scales, how it impacts return path loading for channel change requests and the like,' and you'll start to see large-scale deployments."

Imagine's VBR/StatMux allows operators to boost last-mile bandwidth efficiency by delivering up to 50 percent more standard definition (SD) or high definition (HD) video streams per 256 QAM channel than do constant bit rate (CBR) precursors. While CBR technology effectively 'nails up' a fixed amount of bandwidth, VBR can vary the bandwidth allocation according to stream requirements at a given time.

The efficiency gains translate to delivering 3 HD VBR streams per QAM channel, up from today's 2 HD CBR streams, and to 15 SD VBR streams per QAM channel, up from today's 10 SD CBR streams.

"One of the main drivers for SDV is the ability to add essentially an unlimited programming lineup, with the new limit being the number of people watching unique channels, which in fact is less than the total of channels offered," Adams says. "Another of the key reasons to deploy SDV is to add HD from a competitive point of view. When you talk to programmers themselves about their plans for HD versions of existing channels and second channels, I think the stars align in 2008, in terms of availability of HD programming and the deployment of SDV."

The two suppliers say their solutions comply with de facto open architecture interfaces developed by the operators. This allows "different vendors to source different components of the overall SDV architecture," significantly reducing integration issues and deployment costs, Adams says.

Initially developed by SDV pioneer Time Warner Cable, the specs include interfaces between the QAM modulator and resource management system (RMS) and between the service and SDV client software in the set-top box, such as Time Warner's Digital Navigator client and Comcast's TVWorks client.

"A nice thing about these architectures from Time Warner Cable and Comcast's Next Generation On Demand is there are a lot of commonalities, so we've built our software to meet requirements of both," says Adams, himself a former longtime Time Warner Cable executive.

As further testimony to the open, modular, multi-vendor nature of the emerging SDV standard architecture, Tandberg is offering a solution with or without the RMS component and with or without Tandberg's own QAM modulator. In the case of a standalone OpenStream Digital Services or OpenStream SDV system, Tandberg offers both session management and session resource management, the latter of which is part of what Adams describes as "the operations back office." However, he says, "while we can do resource management, we don't force it on operators. That's our philosophy for all of this. We also build high density QAM modulators, and we're announcing a new one at the show as well. Again our approach is to offer both the SDV system and the edge QAM, but if you have existing QAM modulators, we'll compete, but we won't tie the things together."

Isolating encryption as a component of the open architecture "is another area where operators are getting pretty smart," Adams says. "They have defined a 'Bulk Encrypter' that takes the video, encrypts it and sends it to the QAM modulator.

The effect is that the SDV system and the QAM modulator itself do not have to deal with encryption. It's somewhat transparent to the implementation."

An additional security technology known as Basic Privacy for VOD is being licensed by Comcast, "Basically it's a level playing field," Adams says. "We're finally getting away from the duopoly [dominated historically by end-to-end Motorola and Cisco/Scientific-Atlanta encryption and conditional access systems]. If you look at the set-top with separable security, the set-top doesn't have to know anything about that. In the headend, you have same thing with the Bulk Encrypter. It isolates the conditional access headaches to that one part of the system."

The emergence of products complying with the operators' specifications promises not only SDV bandwidth efficiency and scale, but also to accelerate the operators' ultimate aim to dynamically share last-mile digital channels across SDV, VOD and high speed data services for a kind of ultimate flexibility in digital channel resource usage. "The operators are intent on QAM sharing, because today you have an inefficient situation where they assign 4 QAMs to VOD, and then a separate QAM for high speed data, and then another 4 to 6 QAMs for SDV," Adams notes. "Somewhere along the way, people said, 'This is crazy, because what if my on demand usage is low and SDV usage is high? Wouldn't it be great if they were shared.' We're likely first to see 8 QAMs shared dynamically between SDV and VOD, and that requires common resource management, and in that case we'd work with the resource manager that the operator defines for us and that may be delivered by another vendor."

Despite its newness, Adams says the OpenStream SDV product suite shares part of its name with Tandberg's OpenStream Digital Services platform because it incorporates mature technology from that earlier platform, including "lessons learned" in implementation for scale and reliability, as well as some common software code. OpenStream Digital Services is now deployed to 15 million VOD subscribers worldwide, and while that platform delivers only unicast streams to individual set-top boxes (STBs) from a video server, OpenStream SDV delivers either unicast or multicast to one or more STBs from a linear source or a VOD server.

"A lot of the same problems you had to solve in on demand you have to solve in the switched digital product: reliability, scalability, the best cost/performance, how you make sure the software can recover from a hardware failure," he says. "Many operational and product implementation issues are the same."

"We believe this agreement represents the beginning of a fruitful relationship between Tandberg Television and Imagine," says Marc Tayer, senior vice president of marketing and business development for Imagine. "Tandberg Television has successfully led the industry in opening up the VOD infrastructure, and now they're pursuing the same course with SDV."

Tandberg similarly values Imagine's VBR video breakthrough, which Adams describes as "very revolutionary." For every operator since Time Warner's Full Service Network experiment in the mid-1990s, "VBR has been a gleam in the eye, and the only reason it hasn't been done is the implementation costs of taking a whole series of VBR streams and mixing them to fit in a constant bit-rate QAM channel or ATM channel or satellite channel," he says. "Imagine has basically looked at this problem anew and come up with an extremely clever solution."