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1394 primed for home net revival

Posted: 16 Jun 2006  Print Version  Bookmark and Share

Keywords:IEEE 1394  High-Definition Audio-Video Network Alliance  FireWire 

The latest "Mission Impossible" has nothing to do with Tom Cruise--it's the revival of IEEE 1394 as the fundamental networking technology for the home.

The early buzz over IEEE 1394, also called FireWire, fizzled long ago. Many in the industry lost hope for 1394 as a linchpin of home networking after the technology fell victim to business politics and industry infighting. Nonetheless, promoters who recently gathered in Dresden, Germany for a 1394 Trade Association quarterly meeting insisted that IEEE 1394 is not just back, but never really went away. Their new strategy is to exploit consumers' appetite for HDTV, building on the momentum of the High-Definition Audio-Video Network Alliance's (HANA) emerging specification for sending 1394 signaling over coaxial cables, (1394 over coax).

"Look around," said Jalil Oraee, founder and CTO of Oxford Semiconductor Ltd. After all the talk about wireless or wired Ethernet-based home networks, or the good old coaxial-based home network promoted by the Multimedia Over Coax Alliance, there are still no other technologies with enough bandwidth and distance to distribute multiple HDTV streams while offering clock synchronization, guaranteed delivery of data and QoS, according to Oraee.

Where best-effort-based Ethernet devices could easily crash and introduce random delays, "with 1394, we can send not only IP packets, but also ensure QoS," Oraee said.

Technologically speaking, many in the industry agree that IEEE 1394 may, in fact, still have a lot going for it. Its failure to ignite the home-networking market "wasn't the 1394 industry's fault," said Richard Doherty, research director of The Envisioneering Group. Rather, the consumer electronics (CE) industry's initial enthusiasm for 1394 was "derailed by cable industry inaction" and "possible subterfuge," Doherty said.

In fact, at one point, IEEE 1394 appeared to have the inside track as the preferred home-networking medium. A long, hard negotiation between the cable and CE industries produced an agreement mandating that U.S. cable operators install 1394 in every STB. The agreement was ratified by the FCC.

Despite the FCC's longstanding approval, however, James Snider, executive director of the 1394 Trade Association complained that "most cable operators in the United States are not delivering functioning 1394 ports."

Doherty confirmed this. "The 1394 connector is there, but the software protocols are not." He added, "Comcast flatly refuses to give cable subscribers a 1394 working box, despite the 2004 FCC directive that they must."

Other industry analysts observed that Scientific-Atlanta, one of two STB vendors dominating the U.S. market, won't provide the 1394 software stack to make its boxes work with 1394. Why? Because U.S. cable operators and cable-box vendors prefer not to see their traditionally-closed business invaded by the CE industry.

Brian O'Rourke, senior analyst at In-Stat, put it bluntly: "As an interface technology, 1394 has done fairly well. As a networking technology, it has been a failure." But even O'Rourke believes the emerging HANA may be "a boon" to 1394 in the CE world. "HANA offers 1394 an opportunity to become a viable networking technology," he said.

HANA promises to enable households to simultaneously stream five high-definition signals within the home. HANA maintains that a 400Mbps data rate, enabled by the 1394 specs, can do the job while keeping programming content secure by means of the so-called "5C" content-protection scheme. HANA has backing from a wide range of companies, including movie studios (Warner Bros. and NBC/Universal), cable companies (Charter), CE companies (Samsung) and chipmakers (Texas Instruments).

"We see 400Mbps as a required minimum," said Hans van der Ven, chairman of the 1394-over-coax working group within the 1394 Trade Association. Even if they don't own five HDTV sets, consumers doing a trick play such as fast-forward on a 20Mbps HD stream on a home network could easily use up five times that bit rate, he explained. HANA has a road map to move to a data rate of 800Mbps by 2009, van der Ven added.

Asked about 1394's role in HANA, van der Ven, an independent consultant at PC & TV-AV Connections and a former Panasonic executive, said, "While HANA promotes its vision, we write standards." The 1394-over-coax specification aims to leverage the coaxial cable already installed in many U.S. homes. "You need 1394 for two reasons: when you want to record HD programming, and if you want to move it around anywhere else in the house," van der Ven summed up.

Although IEEE 1394 was eclipsed by the high-definition multimedia interface (HDMI) as a point-to-point interface between a cable STB (or HDTV receiver) and a display, HDMI doesn't work well as the interface between an STB and a home recording device. Since it's a one-way interface for sending uncompressed digital signals from one device to another, HDMI will end up transferring too large a file to a recording device, thus compromising the recording device's storage capacity. In contrast, 1394, which is designed to send compressed signals, is optimized for recording content from a DTV, as well as playing it back.

Bandwidth junkies
Even Microsoft Corp. seems to agree. While the software giant won't be ready to support 1394b in the upcoming OS Vista, it plans to ship 1394b support in the service pack. "We have PC OEMs' interest; 1394 will be important for high-bandwidth junkies as an interface for external storage systems," said Mark Slezak, program manager of Microsoft's Windows Device Experience Group.

HANA, however, lacks a CE heavyweight--such as Sony or Matsushita--in its camp. Both Sony and Matsushita are pursuing Ethernet as an A/V home-networking medium via the Digital Living Network Alliance (DLNA).

Acknowledging that Panasonic has not joined HANA, Paul Liao, VP and CTO of Panasonic Corp. of North America, said, "Today, all sorts of networks--WAN, LAN, data, voice, video--are moving toward being based on IP protocols. For this reason, Panasonic sees there are great benefits for home video and audio entertainment networks to use IP-based protocols rather than IEEE 1394 protocols, which HANA is based on."

The 1394 Trade Association doesn't agree, nor do HANA promoters. HANA chairman Jack Chaney, director of the DMS Labs at Samsung, flatly said, "HANA is IP-based and guarantees delivery." Peter Johansson, VP of Congruent Software Inc., concurred. "Ethernet and IP are not one and the same thing. IP is so easy to carry. Ethernet carries IP, 1394 carries IP, and coax carries IP."

Chaney remains confident that other companies will join HANA.

"Large corporations' strategies are complex and very secret," he said. "If the objectives of HANA and the 1394 Trade Association are achieved on schedule, then these large corporations will be part of the flow to HANA."

The technical work within the 1394 group is converging on IP as the control plane for all network devices (i.e. TCP/IP encapsulation for A/V devices). Johansson is proposing to transport A/V streams as out-of-band isochronous data while connecting link segments with L3 bridges.

In the proposed HANA-based home network architecture using 1394 and 1394-over-coax, the group plans to put in place a "bridge" that translates a 1394 bus to 1394-over-coax or, in the future, another controller that bridges 1394 and Ethernet networks. It will also install a proxy device that helps the network discover what legacy devices are out there, and send control commands. The proxy device would translate HANA commands--transported on IP--into A/V device commands and send them, Johansson explained. "Proxy devices are like having a guide and an interpreter in one," he said.

Indeed, beyond the lack of clock synchronization, the biggest issue with DLNA for 1394 promoters is its treatment of legacy A/V devices, according to van der Ven. "The new Ethernet router that comes with the latest Universal Plug & Play features talks to DLNA devices, but it stops legacy devices from interfering"effectively banishing the legacy products from new home network technologies.

- Junko Yoshida
EE Times




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