In the long-standing debate over thick- and thin-client set-tops, the importance of the broadband networks that support them has been somewhat lost in the shuffle.
But recent interactive-television developments at AOL Time Warner Inc. and AT&T Broadband have thrust the significance of the network back into the forefront.
For example, Headend In The Sky — and its digital-delivery system — is expected to play a key role in AT&T Broadband's initial ITV strategy, which uses the widely deployed Motorola Broadband Communication Sector DCT-2000 digital set-top.
And AOL Time Warner has handed down a strong endorsement for network-based PVRs, on-demand television and targeted advertising.
Though the technology for those tasks is solid, scaling a network-based arrangement for applications such as the PVR is still the next obstacle to overcome, newly installed AOL Time Warrner Interactive Personal Video Group president Jim Chiddix said earlier this month.
Though set-tops — and the future bells and whistles that will be contained within them — grab much of the spotlight, the network remains an even more important element in advanced interactive applications. Some in the industry even believe that the thick-versus-thin debate has, to a degree, been blown out of proportion.
"The whole construct of thick-versus-thin is not one that we particularly agreed with or liked," said Scientific-Atlanta Inc. subscriber division vice president of product strategy Bob Van Orden.
That's partly because S-A's baseline 2000-class Explorer boxes blasted from the blocks with a real-time operating system, Internet-protocol address capabilities and the ability to communicate directly with headends and servers — which comes in handy when addressing core interactive applications like video-on-demand, electronic mail and instant messaging.
S-A has a range of boxes that tops out with the PVR-enabled Explorer 8000, "but we use the same network and the same signaling and the same infrastructure for applications," Van Orden said.
S-A's platform, which is widely deployed by Time Warner Cable, uses a broadcast file system that essentially treats the network like a hard drive. When a user hits the e-mail button, the box fetches the information from the network so it appears as if the application resides on the set-top.
When a user switches to another application, the memory on the box that was using e-mail is freed up "in a matter of seconds," Van Orden said. "It's an elegant trick."
Motorola, the largest cable set-top maker, expends about 85 percent of its research-and-development effort on the network side, estimated Mark DePietro, vice president of Motorola Broadband's DigiCable unit, which works closely with HITS on its ITV distribution strategy with affiliated MSOs.
"It's something very important to us," he said.
The HITS distribution of ITV middleware closely resembles the techniques now used to send and update interactive programming guide information to digital boxes, DePietro said.
In that broadcast arrangement, a large download stream that originates from HITS is received by local headends, and does not require a real-time return path, he said.
Though the network is a powerful component for broadcast and true interactive ITV applications, Charter Communications Inc. continues to champion the high-end digital set-top.
Charter is gearing up for a DCT-5000 trial in St. Louis, and plans to deploy its first set of those boxes to homes in the fourth quarter of 2001.
Moving beyond rather static ITV implementations, Charter's trial — using content from corporate cousin Digeo — will take advantage of the box's broader range of processing muscle power. It will offer a walled garden filled with more complex Flash animation, richer graphics and streaming media, said Charter director of new-product implementation Ingrid Long.
Charter has not announced which middleware platform it will use for the trial.
Though Charter will use the original DCT-5000 in St. Louis, the MSO plans to start a migration to more powerful DCT-5100-class boxes in the first or second quarter of 2001, Long said.
At the same time, the client-network relationship "is really just a balancing act," Long said. "You look at the limitations that you have in the box and the limitations you have on the network, and you try to maximize both of those."
Charter will deploy applications that are both server- and set-top-intensive, she said. "It depends on what we're trying to deploy and what we're trying to do."
Charter's focus is presently on the set-top box-based PVR.
"That's the most imminent, and we have a very aggressive plan for that," Long said, noting that Charter is exploring the server-based PVR, though that technology is relatively in its infancy.
"Right now set-top box PVRs are on a bit of a faster track," she said.
A set-top with a hard drive can also remove some network congestion caused by applications like VOD, said Charter staff engineer Pragash Pillai.
"With a hard-drive PVR option, you can offload your network streaming usage, rather than streaming everything [on demand] from the headend," he said.
For example, downloading some titles to set-tops during off-peak hours — and leaving them available for subscribers if and when they decide to order — might alleviate some stress on the network.
That storage model might apply well to sought-after VOD movies, but probably not for I Love Lucy
reruns or other TV shows with lower consumer demand, Pillai said.
"You need to learn customer behavior before you can push the content," he said.