Data centers utilize multiple networks that present operational and maintenance issues as each network requires dedicated electronics and cabling infrastructure. Ethernet and Fibre Channel are the typical networks, with Ethernet providing a local area network (LAN) between users and computing infrastructure, while Fibre Channel provides connections between servers and storage to create a storage area network (SAN). Fibre Channel’s T11 technical committee and theInstituteofElectricaland Electronic Engineer’s (IEEE’s) DataCenterBridging committee have defined standards to converge the two fabrics into a unified fabric with Fibre Channel over Ethernet (FCoE).
What is FCoE?
FCoE is simply a transmission method in which the Fibre Channel frame is encapsulated into an Ethernet frame at the server (Figure 1). The server encapsulates Fibre Channel frames into Ethernet frames before sending them over the LAN and de-encapsulates them when FCoE frames are received. Server I/O consolidation combines the NIC and host bus adapter (HBA) cards into a single converged network adapter (CNA), which reduces server cabling and power/cooling needs. At present, the Ethernet frame is removed at the Ethernet edge switch to access the Fibre Channel frame, which is then transported to the SAN. Fibre Channel encapsulation requires use of 10 Gigabit Ethernet transmission electronics as well as provides for increased server to SAN connectivity.
FCoE encapsulation standards activity took place at the Fibre Channel T11.3 committee. Fibre Channel is a deterministic protocol that guarantees delivery of information. Native Ethernet has not been deterministic and has relied on transmission control protocol (TCP) to re-transmit dropped frames. With FCoE, the Ethernet transport has been required to be updated to ensure that frames/packets are lossless without using TCP/IP protocol. The new enhanced Ethernet standard is called converged enhanced Ethernet (CEE). CEE standards activity took place at the IEEE 802.1 Data Center Bridging working groups and was completed in 2011.
To read more on FCoE view this Corning White Paper.