Fcoe Protocol Stack - IBM V7000 Introduction And Implementation Manual

11.4.1 FCoE protocol stack

The FCoE requirement is the use of a lossless Ethernet, for example, one that implements
the DCB extensions to Ethernet as described previously.
The structure of FCoE is that the upper layers of FC are mapped onto Ethernet, as shown in
Figure 11-8. The upper layer protocols and services of FC remain the same in an FCoE
deployment. For example, zoning, fabric services, and similar functions still exist with FCoE.
The difference is that the lower layers of FC are replaced by lossless Ethernet. Therefore, FC
concepts, such as port types and lower-layer initialization protocols must also be replaced by
new constructs in FCoE. Such mappings are defined by the FC-BB-5 standard.
Figure 11-8 FCoE protocol mapping
Figure 11-9 shows another perspective on FCoE layering compared to other storage
networking technologies. The FC and FCoE layers are shown with the other storage
networking protocols along with iSCSI.
In general, an FCoE network contains servers, lossless Ethernet (DCB-capable) switches,
Fibre Channel Forwarders (FCFs) that provide FC fabric services, and storage devices. An
existing FC SAN may or may not be present. With compute node connectivity to IBM Flex
System V7000 Storage Node, the connection link is by I/O module lossless Ethernet FCF
switches, a connected FC SAN does not have to be present.
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Chapter 11. SAN connections and configuration