Understanding Fibre Channel Virtual Links

A virtual link emulates a secure point-to-point connection between the virtual node port (VN_Port) of a Fibre Channel over Ethernet (FCoE) node (ENode) and the virtual fabric port (VF_Port) of an FCoE forwarder (FCF). The combination of the FCF media access control (MAC) address and the VN_Port MAC address uniquely identifies each virtual link. Uniquely identifying each virtual link enables the logical separation of traffic that belongs to each virtual link. A single physical link between an ENode and an FCF can carry multiple virtual links and maintain secure, separate transport of traffic on the different virtual links.

Virtual links are necessary because Fibre Channel protocol does not recognize multipoint-to-point connections. Even when multiple connections are aggregated on one physical port, FCoE Initialization Protocol (FIP) presents each virtual link as an individual point-to-point link between an ENode VN_Port and an FCF VF_Port.