August 1, 2009
Gateways to an IP Future: Operators Open to the Idea
By Linda Hardesty, associate editor, and Jonathan Tombes, editor
AT&T has one. Virgin Media is working on it. These devices could reduce costs and satisfy real consumer demand for video routed to IP-enabled endpoints.
Customer premise equipment (CPE) has always been an expensive proposition. One device multiplied by hundreds of thousands, or more, adds up quickly.
That kind of scale helps explain why MSOs have a reputation for thinking long and hard before deciding to upgrade equipment. In Time Warner Cable’s case, the multiplier for set-top boxes is two million annually. And that’s just set-tops. Comcast bought some six million (admittedly cheaper) digital terminal adapters (DTAs) in 2008.
Moreover, as MSOs moved into triple-play service delivery over the past decade, they increased the kinds of CPE that they buy, maintain, and provide to subscribers.
Moving some of that inventory into consumer hands was supposed to have been one of the benefits of the OpenCable initiative. Combined with the federal mandate that all boxes deployed by July 1, 2007 have separable security, OpenCable’s OCAP or tru2way platform has driven the development of set-tops that consumers could purchase and take with them as they moved from one cable system to another.
The number of sufficiently affluent, motivated and mobile households, however, has just never been high enough to drive much of a retail market for set-tops.
The integration of tru2way technology into high-definition television sets (HDTVs) — essentially embedding set-top functionality within a flat-panel TV set — has changed that consumer equation to some extent. But when it comes to the larger category of CPE, the pace of change is being driven less by legacy regulatory requirements and more and more by consumer demand to watch video on devices other than the TV set.
Subscribers also want these various and mostly Internet protocol (IP)-enabled video-viewing devices to be networked.
The bottom line: While broadcast video over MPEG is a great way to deliver high-quality, high-quantity content to a mass audience, there is a growing demand for more video via IP. One option for getting video to IP devices is with a home gateway.
Let’s briefly touch several categories and related technologies.
One type of home gateway emphasizes video. Content is received by the gateway in MPEG; then the device transcodes any portion of the content headed for an IP device.
Another so-called gateway — a DOCSIS set-top gateway (DSG) — is less a device than a specification for non-proprietary set-top messaging. A DSG-enabled set-top, however, does have an embedded cable modem. As discussed over the years, MSOs could leverage the modem to accelerate additional interactive and video services, but its potential remains largely untapped.
A related category, championed by chipmaker Texas Instruments, is the use of DOCSIS 3.0 channel bonding techniques to combine narrowband and wideband tuners to capture an entire spectrum and to transform devices into full digital gateways.
Then there are high-speed data gateways, usually embedded modems and wireless routers. These have typically been data only. But the latest iteration of Wi-Fi technology, 802.11n, could be a game changer for some service providers.
At the CableLabs 2008 Winter Conference, for instance, Ruckus Wireless demonstrated an 802.11n home networking system capable of distributing multiple streams of high-definition IPTV content throughout a home. Attendees voted it, from a showcase of nine vendor demos, as the "best new idea."
One more type of of gateway could also incorporate femtocel technology, serving to backhaul wireless voice traffic.
No preference, yet
Given the fluid market, some industry leaders characterize this as a time to define, discuss and evaluate.
"I think it’s safe to say there are many interpretations of gateways," said Doug Ike, VP of advanced video and applications engineering, Charter Communications. "The vendor community and MSO community are in various stages of communication about what this device should have."
When it comes to home gateways, the industry has not settled on a clear preference, said Steve Necessary, VP of video product development and support for Cox Communications.
"A lot depends on where you think the video delivery system is heading and how quickly it will get there," said Necessary. "If you say ‘one day we need an all-IP video delivery,’ then you might say ‘let’s go with the data gateway because over time more video delivery is going to be data-type.’"
"Many set-tops have modems built into them," said Ike. "But whether the intent is to use in the gateway manner has not been there in the past. Going forward, we are all looking at set-tops that have DOCSIS capability."
While capital cost is a big consideration, when it comes to any kind of CPE, gateways could potentially save money. Rather than replacing set-tops, gateways could work with existing equipment and at the same time provide a means for connecting equipment in the home.
Networking is "one attractiveness of gateways," said Ike. "But the economics of transcoding the gateway may not be there yet."
Virgin Media, AT&T
Motorola is working with Virgin Media, the major cable operator in the United Kingdom, to develop what it is calling a "transport gateway."
"The transport gateway’s main purpose is to take MPEG and translate it to IP," said Chris Kohler, senior director of engineering with Motorola. "We believe it’s more efficient to re-use the existing MPEG infrastructure and have a gateway in the home to do the translation."
The transport gateway is equivalent to the home video gateway.
Vendors know the cable industry is loath to replace legacy set-tops. Motorola’s transport gateway is designed to work with the existing set-top and cable modem at the subscriber’s house. "You don’t replace anything," said Kohler. "It’s an overlay. You wouldn’t swap out existing set-tops."
Whether MSOs will be convinced that an "overlay" is saving them money on capital expense is yet to be seen. But one benefit of the new gateway is to work with other devices.
The concept is similar to AT&T’s U-verse, which deploys a basic high-speed data gateway in the home that then transports data and video to either a cable modem or an IP-based set-top box.
Relatively dumb, the IP-based set-top is very functional. "The IP-based set-top boxes are tuner-less. So features like picture-in-picture work on any TV," said Jenny Bridges, a spokeswoman for AT&T.
"While the middleware in a cable set-top box resides within the box itself, the middleware for the Microsoft TV IP-based video box resides in the network. With much of the processing done in the network, the set-tops are much less processing-intensive," Bridges explained.
Kohler said Motorola’s transport gateway would have more intelligence than the U-verse gateways, including the ability to connect to other IP-based communications devices at the consumer premises. He said the Moto gateway would be tied into the network’s back office to manage IP video content as it gets to different IP clients.
But while Motorola and Virgin Media are still working on the transport gateway, AT&T continues to announce more features to U-verse. In June, the company rolled out a total home DVR feature, a new On Demand Top Picks application and navigation upgrades.
"Enhancements are pushed out seamlessly to customers over our IP network," said Bridges.
"It’s an overlay. You wouldn’t swap out existing set-tops." Chris Kohler, Motorola
With the popularity of over-the-top video, the cable modem can carry some of the burden of video.
But if too much video starts flowing through the modem, Internet speeds will be impacted. "It requires dedicating some number of receive channels in the modem to receive the IPTV channels," said John Horrobin, manager, cable product marketing, Cisco. "The downside is when you’re trying to deliver a high-speed data service, the rate is dependent on how many receive channels are available."
But operators are more concerned about the overall design of their network architectures than the limitations of current modems or set-tops. "You can always engineer a solution," said Ike.
"Different operators look at it in different ways," said Jim Strothmann, director of product strategy and management, Cisco service provider and video technology group. "Am I going to replicate my entire video offering (on IP) or supplement my video offering?"
"There is no ideal solution," said Dominique LeFoll, CTO at Amino, a maker of CPE for broadband.
"The cable industry is going to have to adopt a hybrid model. That is what is most likely to happen. Take IP technology and adapt a little bit," she said.