Sizing Up 8-Gbit/s FC

A movement's underway to add 8-Gbit/s to the list of Fibre Channel speeds.

Groups within the Fibre Channel Industry Association (FCIA) and the InterNational Committee for Information Technology Standards (INCITS) are talking of adding the new speed to their standards, according to Skip Jones, chairman of the FCIA Speed Forum Committee, who also works for QLogic Corp. (Nasdaq: QLGC).

The FCIA recently voted to extend its Fibre Channel "roadmap" to include 8-Gbit/s speeds for the electrical, copper-based interconnects inside disk drives, controllers, storage cabinets, and other gear (see FCIA Adopts 8-Gbit/s Fibre Channel). And that's led to talk of adding 8-Gbit/s to Fibre Channel fabric gear as well.

If the FCIA committee agrees, it could vote on new specs as early as June, according to Jones.

Meanwhile, Jones says, INCITS may consider adding 8-Gbit/s Fibre Channel to its electrical interconnect list, although no work has yet been undertaken. No one at INCITS had responded to calls or email for clarification at press time.Hang on. Don't we already have enough Fibre Channel speeds? After all, 4-Gbit/s Fibre Channel is starting to show up on show floors, and vendors maintain it will start hitting serious procurement lists by the end of this year (see 4-Gig for Show). And what about 10-Gbit/s Fibre Channel, not to mention InfiniBand?

Jones says 10-Gbit/s Fibre Channel equipment is still expensive to build, and, due to its encoding scheme, not backward-compatible with 1-, 2-, and 4-Gbit/s Fibre Channel kit. An 8-Gbit/s spec, however, would double the speed of 4-Gbit/s while sharing the same encoding with lower-speed gear, ensuring automatic compatibility -- and lower development costs than 10-Gbit/s.

As for InfiniBand, Jones says it's not selling as a SAN solution anyway. "I suppose this could be just one more reason not to do InfiniBand," he quips.

Not everyone agrees. While 14 of the 21 principal FCIA vendors polled on the issue of 8-Gbit/s voted "yes" to the recent interconnect roadmap, Jones says one voted "no," two abstained, and four didn't vote.

The ballots were closed, but principal members of FCIA whose endorsements weren't mentioned by Jones or listed in the FCIA public statement about 8-Gbit/s interconnect include Agere Systems Inc. (NYSE: AGR.A), Broadcom Corp. (Nasdaq: BRCM), IBM Corp. (NYSE: IBM), and Sun Microsystems Inc. (Nasdaq: SUNW).Of course, this doesn't mean the above vendors disagree with the FCIA committee's suggestion. And Jones says switch vendor principal members were supportive, at least verbally (their votes are unknowns).

Bottom line? A new speed is still just talk. During a recent Byte and Switch Webinar on 4-Gbit/s Fibre Channel, the matter of 8-Gbit/s was raised, according to moderator Greg Schulz of the Evaluator Group.

No one had strong feelings either way, he notes. "I don't think it will be needed for at least two to three years," he says. But he questions whether, given the need to plan ahead for higher-speed SANs, it wouldn't be better to start thinking beyond what's expedient now, especially given that 10-Gbit/s gear will eventually come down in price as well. "We have to ask about what's beyond 10-gig," he contends. "Should we double our speed, or go to 20, 40, or even 100 Gig?"

Mary Jander, Site Editor, Byte and Switch