The DLNA, now in its fourth year of operation, is aggressively and successfully addressing the issue of interoperability among devices in the consumer's digital-AV universe. Although the alliance has a broad and ambitious scope and goal—encompassing consumer-electronics devices, PCs, and mobile devices such as portable video players and multimedia cell phones—the DLNA is making unmistakable and unprecedented progress, as is evident by a growing slate of DLNA-certified products in the marketplace.

The DLNA targets a consumer-focused ecosystem of interoperable products that allows access to and enjoyment of content in a substantially better way than today's confusing and inconsistent home-networked world. The organization is working to provide consumers with seamless and convenient access to all forms of content in a manner that is transparent, that protects the consumer's investment in commercial content, that protects the rights of content owners, and that respects the consumer's sensibilities and expectations of access and usability. These goals are collectively consistent and synergistic. With its progress toward these goals, the DLNA is enabling the next killer app: easy access to content, anywhere, at any time, and on any authorized device in the consumer's interoperable domain.

Through its efforts, the DLNA's goal is to bake a bigger pie from which all participants can take a rightful piece. This goal stands in contrast to current examples of individual companies that are working to make a pie that they wholly control. It also stands in contrast to recent industry activities that hoped to create interconnected technology islands that stood in isolation, before it became clear that connectivity to the global Internet would become a business necessity, as it now has.

To be clear, the DLNA is working to create a thriving, sustainable ecosystem that is an integral part of the Internet, and, to this end, the DLNA's technology platform is founded on proven and ubiquitous Internet protocols. The DLNA ecosystem includes device manufacturers, service operators, retailers, and content owners. And it is an open ecosystem, in which all parties can participate and from which all parties can derive business value.

To achieve its admittedly ambitious goals, the DLNA must establish an actual, adequate, and usable platform without going too far up the stack and without falling short of the goals. History provides a long list of efforts with scopes too narrow—or too broad—to be commercially useful.

The DLNA has carefully chosen its target for the overall interoperability stack. At the lowest level of that stack, the DLNA has established 802.11a, b, and g, plus wired Ethernet. Although the DLNA guidelines spell out these physical interfaces, other physical interfaces can carry the DLNA stack, provided that they have IP (Internet Protocol) mapped onto them. Future DLNA guidelines may include other physical interfaces, depending on the interests and support of DLNA members.

Moving up the stack, the DLNA has chosen the UPnP (Universal Plug-n-Play) Device Architecture, or UDA, Version 1.0. The UDA provides network autoconfiguration, device discovery, and device capabilities and service discovery. Next, the DLNA guidelines document how to use the UPnP CDS (Content Directory Service) for content discovery and selection. Above that, the DLNA guidelines identify HTTP (Hypertext Transfer Protocol) for device communication and content movement across the network.

On top of this stack is the DLNA media-format-interoperability model. This model identifies a set of media formats that are necessary to achieve interoperability. Each format in the set of required formats is an open standard, and the DLNA bylaws themselves legislate this restriction. This step ensures that open industry standards will provide the foundation of media-format interoperability for all time.

In addition to the required media formats, the DLNA has published a set of optional media formats. Manufacturers of DLNA-compliant devices are free to implement and use any documented optional format, provided that it enables them to interoperate successfully. In the event that two devices do not implement the same optional format, they must then use one of the required formats to achieve interoperability.

This scenario means, for example, that a DLNA-compliant server must transcode content from an optional format into one of the required formats in the event that the server is attempting to stream content to a player or a rendering device that implements only one of the required formats or one that implements a different optional format. Using this mechanism, the organization seeks to ensure that DLNA-certified devices will meet expectations when the consumer discovers some interesting piece of content and hits the virtual "play" button.

This DLNA stack provides a solid foundation for interoperability. Content of all types, including commercial content, will flow across that foundation. To protect commercial content, the DLNA has now finalized its Link Protection Guidelines, which the organization will publish in the near future. These guidelines rely on well-known and trusted content-protection technologies to meet first-stage, near-term content-protection requirements.

The DLNA has recently chartered a new subcommittee to continue work on commercial-content interoperability. In setting up this work, the DLNA leadership expended great effort to set directions and realistic, but commercially useful, goals. The first fruits of this effort are the aforementioned Link Protection Guidelines. The DLNA based the next goal on the realistic expectation that at any point in history, more than one DRM (digital-rights-management) system will be operating in the world of consumer devices.

Choosing and mandating a single DRM system for all devices, therefore, are unrealistic goals, and achieving these goals is not the DLNA's intention. Instead, the DLNA is seeking technology approaches that address what the organization calls DRM interoperability. "DRM interoperability" means that, even if you own a variety of content that an array of DRM technologies protects and even if you own a variety of devices that collectively implement a multitude of DRM technologies, you should be able to access all content that you are authorized to access on all legitimate devices that you own. This goal is another ambitious one, to be sure, but one that is at hand, thanks to the realization, among all participants in the consumer-product and commercial-content value chains, that network interoperability is the foundation for the next killer app.

In its short existence, the DLNA has realized a rock-solid platform of interoperability based on proven, ubiquitous, and open industry standards; a certification and logo program that speaks to the consumer; and an effective process for building on the interoperability platform and managing the evolution of technology. These achievements represent a degree of collaboration we've never before witnessed in any standards-setting body. Moreover, DLNA has chosen the right target, going as far up the stack as necessary to realize interoperability without going too far up the stack or limiting member companies' ability to differentiate.

DLNA has earned the interest and participation of content owners and service operators, thereby ensuring that commercial content will flow and that the DLNA platform will support the deployment of new services and content businesses. Device retailers are also actively participating in DLNA efforts to bring the interoperable home network to the consumer. In short, DLNA is delivering on its promise, and the future is bright.

Scott Smyers is the chairman of the DLNA. He is also the vice president of the Network and Systems Architecture Division of the Platform Technology Center of America at Sony Electronics.

Thanks to an FCC (Federal Communications Commission) mandate, all high-definition cable set-top boxes include a 1394 port. However, most of these ports remain unused.

There are two reasons for this situation. First, cable set-top boxes render a rich GUI (graphical user interface), which they then send in uncompressed form to the TV in one of three ways: over DVI (Digital Visual Interface), over HDMI (High-Definition Multimedia Interface), or as an analog signal. No current home-networking technology, including Gigabit Ethernet, can cost-effectively support uncompressed high-definition signals.

The second reason that cable companies have ignored the 1394 port is that they do not install Category 5 or 6 UTP (unshielded-twisted-pair) wire. They pull coaxial cable. Faced with the choice of training thousands of installers to install thousands of miles of UTP cable in homes or placing a set-top box at each TV, they have opted for distributed set-top boxes.

The HANA (High-Definition Audio-Video Network Alliance) is working with member companies and cable companies to enable the networking of an OCAP (OpenCable Application Platform) GUI over 1394. And the 1394 Trade Association, in partnership with HANA member companies, is developing 1394 over coaxial cable at 400 Mbps. These developments will allow cable companies to finally employ those 1394 ports. And, from the consumer perspective, these changes would allow a single set-top box to drive displays throughout a home.