Ethernet Storage to Morph Again

Cisco is spearheading the creation of a spec that would allow Fibre Channel to run directly over Ethernet in competition with iSCSI. And it looks as though Nuova Systems, the startup that emerged from Cisco storage spin-in Andiamo Systems, will play a key role. (See Vendors Propose FCOE and Andiamo Crew Reunites With Cisco.)

Claudio DeSanti of Cisco is vice-chair of the ANSI T11 committee, which is overseeing the Fibre Channel over Ethernet (FCOE) specifications, and he authored the project proposal. Silvano Gai, a former Andiamo and Cisco employee, is helping to author the spec. Gai and former Andiamo colleague Luca Cafiero co-invented Cisco's Data Center Ethernet (DCE) spec, which includes a way of mapping FC over Ethernet, and for which they filed a patent on behalf of Cisco in 2005.

Gai and Cafiero now work at Nuova Systems, in which Cisco has a sizeable investment. And it looks as though they and other Nuova colleagues could be among the first to issue products supporting the new spec -- though Nuova hasn't officially provided any timeline for its first products.

FCOE will use framing techniques contained in FCIP (Fibre Channel over IP, based on IETF and ANSI standards) and the pause mechanisms for Ethernet switches specified by the IEEE. By effectively combining the techniques, DeSanti and Gai propose to run Fibre Channel directly over Ethernet to compete with iSCSI in all kinds of data centers.

"FCoE would enable SAN traffic to be natively transported over Ethernet networks, while protecting and extending the investment that customers have made in storage networks," writes DeSanti in an email today. "FCoE would give customers a new choice for more pervasive server connectivity in the data center, and complements today's existing connectivity and protocols used in storage and data center networking."In his project proposal to the T11 committee, DeSanti specifically refers to iSCSI: "This mapping provides several technological benefits over the currently defined Fibre Channel over IP (FCIP) mapping and gives a significant business advantage to Fibre Channel over competing technologies, such as iSCSI, because it provides seamless compatibility with existing storage, drivers, and management tools," he states in the document. He notes that expanding the specs could also encompass Sonet for use in metro Ethernet networks as well as data centers.

Supporters of the spec, including Brocade, EMC, Emulex, IBM, Intel, Nuova Systems, QLogic, and Sun, apparently view the protocol as an opportunity to leverage their existing FC investment while promoting their sizeable interest in Ethernet. All are saying that 10-Gbit/s Ethernet will be key to making the whole thing take off.

"FCoE is not tied inherently to 10GbE. However, with the assumption that both storage and networking share the same wire for systems that might otherwise use 4G FC today, the expectation for products arriving in 2009 with the standard is that 10GbE would be used rather than 1GbE," writes Taufik Ma, VP of marketing, intelligent networking products, at Emulex.

The FCOE spec is set for initial public review in 2008, which should give stealthy Nuova and the other vendors involved ample time to develop new adapters and switches in support of it.

One analyst, who asked not to be named, doesn't see the advantage in competing with iSCSI. "I don't see it as efficient to put an Ethernet envelope over FC, which envelopes SCSI, instead of ripping off the FC envelope and putting on iSCSI," he says.Another analyst, Greg Schulz of the StorageIO consultancy, sees Cisco's strategy as part of a larger evolution toward hybrid switching and virtual I/O, as evidenced in the work of companies like Woven Systems and Fabric7. "Fibre Channel and Ethernet have traded technology back and forth historically," Schulz says.

Schulz sees the new FCOE as an attempt to create an "MPLS (Multiprotocol Label Switching) look and feel" for data center and storage networks. (It's perhaps no accident that the Nuova team includes MPLS experts.) It would also offer a common hardware base for Ethernet and Fibre Channel.

Whether FCOE can take the place of iSCSI, at least in networks where FC SANs and LAN-based servers and NAS are consolidated, remains to be seen. But Schulz says it's likely other key players, like Broadcom, PMC-Sierra, and Microsoft, would join the party as it gains momentum.

For now, it seems some of the big players are mulling the ramifications. Notably absent from the bandwagon are HP and NetApp.

While HP had no comment at press time, NetApp spokesman Eric Brown responded thus: "We examine our research and development efforts very carefully before making broad market commitments. We see no pressing customer need for this at this time but will evaluate our options and what we can contribute if and when a customer need becomes apparent."Mary Jander, Site Editor, Byte and Switch