Overview of FIP
Fibre Channel over Ethernet (FCoE) Initialization Protocol (FIP) is a Layer 2 protocol that establishes and maintains Fibre Channel (FC) virtual links between pairs of FCoE devices such as server FCoE Nodes (ENodes) and FC switches. FIP can also establish and maintain virtual links between FCoE devices and an FCoE-FC gateway (such as the QFX3500 switch), where the gateway acts on behalf of the FC switch.
FIP enables FCoE devices to discover one another and to initialize and maintain virtual links over a physical Ethernet network. This allows FCoE devices in the Ethernet network to access storage devices in the FC storage area network (SAN).
FIP solves the problem presented by the FC requirement for point-to-point connections (FC does not permit point-to-multipoint connections) by creating a unique virtual link for each connection between an ENode VN_Port and an FC switch VF_Port. Multiple virtual links can use a single physical link and virtual links can traverse Ethernet transit (passthrough) switches while appearing to be direct point-to-point connections to the FC switch.
FIP has its own EtherType (0x8914) to distinguish its traffic from payload-carrying FCoE traffic and other Ethernet traffic. FIP operations occur on a per-VLAN basis.
For more details about FIP, see the Technical Committee T11 organization document Fibre Channel Backbone - 5 (FC-BB-5) Rev 2.00 available at http://www.t11.org/ftp/t11/pub/fc/bb-5/09-056v5.pdf.