Setting the Stage for Faster FC

Announcements from Agilent Technologies Inc. (NYSE: A), Intel Corp. (Nasdaq: INTC), and Vitesse Semiconductor Corp. (Nasdaq: VTSS) focus on the emerging market for 4-Gbit/s Fibre Channel equipment, as well as the market for 10-Gbit/s gear.

Here's a quick rundown:

Bottom line? The component vendors say their news foreshadows widespread adoption of 4-Gbit/s Fibre Channel later this year. Further, both see the move to 4-Gbit/s for disk arrays and smaller switches being accompanied by a move to 10-Gbit/s interswitch links (ISLs) in roughly the same timeframe.

Notably, 10-Gbit/s interswitch links already are offered by QLogic Corp. (Nasdaq: QLGC) as part of its SANbox 5200 (see QLogic Gets Stacked and QLogic Stacks SMB Deck).

Vitesse, which also makes 10-Gbit/s ICs, thinks 10-Gbit/s Fibre Channel "front-end SAN" links between switches or directors and end-user hosts will be more widespread by the end of 2004. "Back-end SAN" links at 4-Gbit/s between switches and disk arrays will start showing up in the second half of 2004.Intel also sees 2004 as the year of 4-Gbit/s, with 10-Gbit/s ISLs appearing, followed in 2005 and beyond by 10-Gbit/s FC for high-end servers and storage gear, as PCI-Express backplanes with higher capacity eliminate bottlenecks. "In Fibre Channel, what will happen is that 4-gig will push out the move to 10-gig," says Bob Zona, marketing director for Intel's enterprise optics division.

Vitesse director of storage marketing Bob Rumer thinks the transition to 4- and 10-Gbit/s won't be as difficult as the one from 1- to 2-Gbit/s. "The move was painful," he asserts. But the industry learned the value of backward compatibility and reducing prices to persuade OEMs to buy, he says. The need to maintain parity with emerging IP-based solutions will further spur vendors to price their higher-speed FC wares low enough to keep OEMs happy to stick with Fibre Channel.

There are still plenty of questions on the road to 4- and 10-Gbit/s, however, the main one being that Fibre Channel network distances are halved again when moving from 2- to 4-Gbit/s.

Intel's Zona, for instance, acknowledges that, using 50-micron multimode fiber, an FC network at 4 Gbit/s will be limited to 150 meters, compared with 300 meters at 2 Gbit/s. Distances are further reduced at 10 Gbit/s. Intel's answer is that most data centers don't call for distances greater than 65 meters, so faster Fibre Channel shouldn't be much of a problem.

But for the makers of Fibre Channel switches, the need to add additional credit buffering to accommodate higher speeds remains an architectural challenge, and one that has industry eyes peeled.Mary Jander, Site Editor, Byte and Switch