WideBand dual-channel network combines qualities of Ethernet and ATM to take aim at streaming multimedia
By Stephen Lawton
High-speed networking just got a bit more confusing. A new initiative, aimed at providing near-gigabit bandwidth over existing Ethernet networks, has been launched by a group of hardware vendors.
Dubbed WideBand after the company spearheading the movement, this alternative Ethernet technology is being positioned as a way to deliver high-performance data and streaming video over Category 5 copper cabling to desktops.
Like National Semiconductor Corp.’s foray into isochronous Ethernet in the early 1990s, WideBand uses a dual-channel approach—in this case a separate data and video channel on existing Ethernet links to connect desktops to servers, essentially letting network managers create new, high-speed segments without rewiring. Despite its physical layer differences, WideBand will adhere to existing Ethernet standards for full compatibility with existing network drivers, OSes, and applications.
This is fundamentally a redesign of Ethernet from the ground up, said Roger Billings, president of Independence, Mo.-based WideBand Corp. Billings’ company, along with roughly twelve other companies, launched the WideBand Gigabit Networking Alliance (WGNA) and introduced the technology at Comdex last month in Las Vegas. It offers the compatibility of Ethernet with some of the Quality of Service, flow control, and other features of ATM, he said.
WideBand links will include one full-duplex channel with a useable bandwidth of approximately 534Mbps for traditional data and a second, downstream-only channel with a useable bandwidth of roughly 267Mbps. The latter channel is intended for streaming applications such as video, Billings said. He said that WideBand technology will “cost about the same as 100Base-T.”
To maintain compatibility with Ethernet, WideBand uses existing Ethernet device drivers, Billings said. However, the streaming channel also incorporates four priority levels for class of service, as well as end-to-end flow control. WideBand signaling requires all four pairs in a Category 5 cable, with one pair dedicated to flow control.
Although WideBand could solve some congestion bottlenecks and bandwidth problems, it likely will serve only niche applications, according to Justin Smith, a senior analyst at International Data Corp., a market-research company in Framingham, Mass.
Smith acknowledged that a lot of companies are “experimenting with gigabit like solutions,” such as Adaptec Inc. ‘s port aggregation and Cisco Systems Inc.’s Fast EtherChannel, as alternatives to the 802.3z gigabit-Ethernet approach. However, he said, WideBand’s stability, its proprietary nature, and the need for gigabit-to-the-desktop must be addressed before it gains widespread acceptance.
WideBand’s Billings said the WGNA alliance is considering submitting the technology to the ISO (International Standards Organization) next year for consideration as a standard. The company does not plan to ask the IEEE for approval because the process is “very political” and there is too much emphasis already on existing Ethernet technology, Billings said.
Users who have seen WideBand in action say it holds promise as a low-cost way to support high-powered multimedia applications. Northwest Missouri State University in Maryville has one of its labs wired with a WideBand network. Jon Rickman, vice president of information services at the university, said his lOMbps FDDI backbone is inadequate to deliver video and data services to the student body.
The university provides video lessons over an existing analog network and would like to convert to an all-digital system so that students can exert more control over their materials. The university is testing a WideBand network and is encouraged by the fact that video sent over the streaming channel has no impact on the data network, Rickman said. If these video signals were sent over the university’s primary Ethernet network, he said, they would significantly reduce the bandwidth available to the rest of the university’s users.
However, without the university’s video applications, Rickman said he isn’t sure he could make a business case to buy the WideBand network. Other alternatives, including gigabit Ethernet, would not solve the video problem, he said. “I’m not ready to mix video with my other data,” he said.
Rickman is so sold on the virtues of a separate video channel that he is installing WideBand in two labs that are under construction. Once WideBand is installed in early January, Rickman will have the opportunity to push WideBand to its 300-foot distance limit; his current lab has no runs longer than 60 feet.
WideBand could be a boon for systems managers with network computers. “I wouldn’t try [NCs] with anything other than WideBand,” Rickman said. “We tried to get NCs to work on our [lOOMbps] network,” Rickman said, but the units required so much bandwidth that his existing Ethernet network was unable to feed the applications fast enough. With WideBand, he claims that applications run faster on the remote server than they do from a local disk drive.
Initial WideBand technology is just the start, said Billings. WideBand 2, which is expected to be unveiled in a year, will be specified at 3.2Gbps and require the new Level 7 cable, he said.