Configuring fcoe interfaces, Fcoe overview, Fcoe terminology – Brocade Network OS Administrator’s Guide v4.1.1 User Manual
Page 337
Configuring FCoE interfaces
FCoE overview
Fibre Channel over Ethernet (FCoE) enables you to transport FC protocols and frames over Data
Center Bridging (DCB) networks. DCB is an enhanced Ethernet network that enables the convergence
of various applications in data centers (LAN, SAN, and HPC) onto a single interconnect technology.
FCoE provides a method of encapsulating the Fibre Channel (FC) traffic over a physical Ethernet link.
FCoE frames use a unique EtherType [FCoE uses 0x8906 and FCoE Initialization Protocol (FIP) uses
0x8914] that enables FCoE SAN traffic and legacy LAN Ethernet traffic to be carried on the same link.
FC frames are encapsulated in an Ethernet frame and sent from one FCoE-aware device across an
Ethernet network to a second FCoE-aware device. The FCoE-aware devices may be FCoE end nodes
(ENodes) such as servers, storage arrays, or tape drives on one end and FCoE Forwarders on the
other end. FCoE Forwarders (FCFs) are switches providing SAN fabric services and may also provide
FCoE-to-FC bridging.
The motivation behind using DCB networks as a transport mechanism for FC arises from the desire to
simplify host protocol stacks and consolidate network interfaces in data center environments. FC
standards allow for building highly reliable, high-performance fabrics for shared storage, and these
characteristics are what DCB brings to data centers. Therefore, it is logical to consider transporting FC
protocols over a reliable DCB network in such a way that it is completely transparent to the applications.
The underlying DCB fabric is highly reliable and high performing, the same as the FC SAN.
In FCoE, ENodes discover FCFs and initialize the FCoE connection through the FCoE Initialization
Protocol (FIP). FIP has a separate EtherType from FCoE. FIP includes a discovery phase in which
ENodes discover VLANs supporting FCoE, solicit FCFs on those VLANs, and FCFs respond to the
solicitations with advertisements of their own. At this point, the ENodes know enough about the FCFs to
log in to them. The virtual link establishment and fabric login (FLOGI/FDISC) for VN-to-VF port
connections is also part of FIP.
Network OS supports the following:
• 100G blades
• 40G breakout Inter-Switch Links (ISLs)
• Changes to the way in which the number of FCoE interfaces are created, through the fcoe-enodes
command
• FCoE troubleshooting commands
FCoE terminology
The following table lists and describes the FCoE terminology used in this document.
Network OS Administrator’s Guide
337
53-1003225-04