There has been a lot of discussion about Fibre Channel over Ethernet lately, and in this post I will try to provide an overview of the technology. FCoE is becoming a standard protocol adopted by storage vendors and operating systems to allow Fibre Channel to run over Ethernet. With the adoption of 10 Gigabit Ethernet networks, it makes sense to leverage the 10-GbE infrastructure for storage networking together with IP networking.

In some aspects, FCoE competes with iSCSI, and there is a debate over the adoption and future of these protocols. FCoE is being positioned as an enterprise class protocol and iSCSI as an SMB class protocol. iSCSI is a routable protocol and FCoE operates directly above Ethernet (Layer 2) as part of the network protocol stack. iSCSI, FCIP and iFCP run over TCP/IP.

It makes sense to wait to adopt FCoE and establish a truly lossless Ethernet infrastructure first. Today’s Ethernet is a best effort network, which means that packets can drop, resulting in packet retransmissions or even time-outs. iSCSI is tolerant of packet drops because it runs over TCP/IP, and knows how to recover when needed.

-Ronny Front, GlassHouse Senior Consultant