To date, though, FC-over-Sonet technology has received relatively limited uptake. Recently, Silicon Graphics Inc. (SGI) (NYSE: SGI) demonstrated its CXFS SAN file system sharing data at 8,000 km using LightSand's FC-to-Sonet gateway (SGI Elongates File System).
And there are still a few unknowns about the technology, says Cisco's Engineer: "Service providers aren't really up to speed yet on how to provision storage over Sonet, so it may end up in a finger-pointing scenario."
James Opfer, an analyst at Gartner Inc., sees FC-over-Sonet as an area ripe for takeoff, especially with the immaturity of IP-based storage networking technologies.
Moreover, he says that Sonet's tiered bandwidth options -- which can range from OC1 (51 Mbit/s) to OC192 (10 Gbit/s) -- mean companies aren't forced to overprovision. For example, even if an enterprise were running a 2-Gbit/s Fibre Channel SAN, it might not actually need an OC48 (2.5 Gbit/s) if its disk mirroring application wouldn't fully utilize that link. "The wide range of performance available and the matching wide range of costs [for Sonet] become the critical parameters in the planning process," Opfer says.
Todd Spangler, US Editor, Byte and Switch