The Fibre Channel Industry Association's (FCIA) members have ratified the extension of the Fibre Channel (FC) roadmap to include 8Gbit/s Fibre Channel (8GFC) for copper backplanes and copper cable storage device interconnects. The storage industry is now selling 2Gbit/s Fibre Channel and the road map goes to 4 and then 10Gbit/s as the next step. Why do we need 8Gbit/s?
The answer is twofold: backward compatibility and Ethernet.
10Gbit/s Ethernet is coming and that will raise the potential of iSCSI Storage area networks (SAN). Currently Fibre Channel SANs claim a speed advantage. They must match, if not exceed, Ethernet in raw speed to justify their cost.
The problem with the 10Gbit/s Fibre Channel standard is that it is not backwards-compatible with 1 and 2Gbit/s Fibre Channel in use today. If customers are grouping four 2Gbit/s links together to achieve 10Gbit/s they won't be able to simply insert a 10Gbit/s cable into the setup and reclaim the now unused ports.
When 8GFC products become available, expected to be in the 2007-2008 time frame, customers will be able to preserve their 2Gbit/s and 4Gbit/s FC device investments and avoid a costly fork lift replacement. The FC auto-negotiation feature enables 8Gbit/s products to automatically sense and adapt to the data rate capability of connected lower speed FC products without user intervention. For example, when attaching to a 4Gbit/s product, an 8Gbit/s product will automatically run at 4Gbit/s.
The 4GBit/s standard is progressing. For example, Hitachi GST recently demonstrated a 4Gb/s FCAL data transfer. The FCIA expects that some 4Gbit/s products will be introduced later this year. Work has already started on developng 8Gbit/s product. LSI Logic's development of 8G SERDES cores exemplifies this.
Mike Karp, a senior analyst with Enterprise Management Associates, said, This graceful move to 8Gbit/s over copper continues the development of Fibre Channel, and makes it clear that Fibre Channel vendors are prepared to continue driving the technology to meet increasing IT demands. Backward compatibility being one of those demands.
Users will be able to look forward to a logical, and hopefully cost-effective, migration from 2 to 4 and then 8Gbit/s FC product, which includes the HBAs, switches, directors and storage device controllers.
Hindsight says it is surprising that a non-backward-compatible 10Gbit/s standard was introduced at all. Rip-and-replace upgrades are out of fashion. FCIAS members endorsed the new 8Gbit/s standard and some implied how they regarded the previous 10Gbit/s standard in their statements. I-Tech CEO Steve Bucher said, I-Tech endorses the FCIAs move to support 8Gbs Fibre Channel with backward compatibility to lower transfer rates. We respect our customers investments by consistently promoting backward compatibility in our test solutions." The 10Gbit/s standard clearly did not respect FC customers' investments.
Where this leaves the 10Gbit/s FC standard is unclear. It will not be backward-compatible with the 8Gbit/s standard, meaning fork lifts will be involved in implementing it still. The likelihood is that it will fade into limbo whilst a faster and backwards-compatible standard is developed to follow on from the 8Gbit/s one.
Recently the FCIA announced the shipping of then ten millionth FC port since ANSI approved the FC standard in 1994. The organisation estimates that there are around 100,000 FC SANs deployed around the globe.
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