SAN's Dark Horse Protocol

A reader of our weekly newsletter wrote to complain that I'd misrepresented my column with the headline: "FC vs iSCSI: A Winner Emerges." I'd like to clarify my point, in case anyone else had an issue.

First off, all the talk of a war between iSCSI and Fibre Channel is irrelevant and premature, in my view. Certainly, there are reasons to adopt both technologies. At this point, iSCSI is in the minority when it comes to networked storage: IDC figures put iSCSI at roughly 5 percent of total SANs installed worldwide, versus about 54 percent for Fibre Channel.

Over time this will change, particularly as 10-Gbit/s Ethernet advances in popularity and users start looking for the fastest way to extend storage for virtualized servers on Ethernet LANs.

But that's not my point. Behind the scenes, there is a third protocol coming into play that will affect storage managers as much as anything else. That's data center Ethernet.

Data center Ethernet, or premium Ethernet, is a modified version of Ethernet that is being readied for use with FCoE, the protocol that is aimed at unifying Ethernet and Fibre Channel I/O links in data centers sometime in the foreseeable future. FCoE can't do its job without it.The IEEE has taken up the task of creating data center Ethernet. This includes modifying Ethernet with new congestion notification, enhanced transmission, and flow-control specs for Ethernet in the IEEE 802.1Qau, 802.1Qaz, and PFC groups, respectively.

It adds up to a fresh take on Ethernet -- one that both iSCSI and Fibre Channel will rely on in years to come.

So from my perspective, that means the real winner in the iSCSI versus Fibre Channel contention is really data center Ethernet, a protocol that is possibly worth tracking even more than FCoE.Have a comment on this story? Please click "Discuss" below. If you'd like to contact Byte and Switch's editors directly, send us a message.