Brocade Converged Enhanced Ethernet Administrator's Guide v6.1.2_cee (53-1001258-01, June 2009)

Table Of Contents
2 Converged Enhanced Ethernet Administrator’s Guide
53-1001258-01
FCoE overview
1
FCoE overview
Fibre Channel over Ethernet (FCoE) enables you to transport FC protocols and frames over
Converged Enhanced Ethernet (CEE) networks. CEE is an enhanced Ethernet 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 that enables FCoE traffic and standard Ethernet traffic to
be carried on the same link. FC frames are encapsulated in an Ethernet packet 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 FC
fabric services and FCoE-to-FC bridging (see Figure 1).
The motivation behind using CEE 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 CEE brings to data centers. Therefore, it is logical to consider transporting
FC protocols over a reliable CEE network in such a way that it is completely transparent to the
applications. The underlying CEE 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). The FIP has a separate EtherType from FCoE. The FIP includes a discovery phase in
which ENodes solicit FCFs, and FCFs respond to the solicitations with advertisements of their own.
At this point, the ENodes know enough about the FCFs to log into them. The fabric login and fabric
discover (FLOGI/FDISC) for VN-to-VF port connections is also part of the FIP.
NOTE
With pre-FIP implementations, as an alternative to FIP, directly-connected devices can send an
FCoE-encapsulated FLOGI to the connected FCF.
NOTE
The Brocade 8000 CEE switch supports only directly-connected FCoE devices and complies to the
June 10, 2008 version of T11-FC-BB5.