H3C Technologies H3C S10500 Series Switches - Manual (Page 18)

7
• EtherType 0x8906.
• Destination MAC address/source MAC address—The definitions of this field are different for
switches and nodes.
{
For a switch, this field is the FCoE MAC address of the switch (which can be displayed by using
the display fcoe command).
{
For a node, this field is the fabric provided MAC address (FPMA) of the node. As shown
in
Figure 7 , an FPMA contains the following elements:
− The FC-MAP as the 24 most significant bits.
− The FC ID of the VN interface as the 24 least significant bits.
The FC-MAP takes the value of the switch FC-MAP, 0x0EFC00 by default and configurable by
using the fcoe fcmap command.
Figure 7 FPMA composition
How FCoE works
This section describes how FCoE works on the FCF switch (rather than on the ENode).
Figure 8 Block diagrams of the ENode and the FCF switch
Procedure for receiving and sending FC frames over Ethernet
An FC frame is transmitted over Ethernet using the following workflow:
1. FIP establishes a virtual link between the VFC interface of the FCF switch and one of the following
interfaces:
{
A VN interface of an ENode.
{
A VFC interface of another FCF switch.
2. After the virtual link is established, the FCF switch encapsulates the FC frame in an FCoE frame and
sends it out.
Virtual link
ENode FCF
VN interface VFC interface
FC layer
Ethernet
layer
Ethernet
interface Ethernet
interface
FC layer
Ethernet
layer