NPIV

N_Port ID Virtualization or NPIV is a Fibre Channel facility allowing multiple N_Port IDs to share a single physical N_Port. This allows multiple Fibre Channel initiators to occupy a single physical port, easing hardware requirements in Storage Area Network design, especially where virtual SANs are called for. NPIV is defined by the Technical Committee T11 in the Fibre Channel - Link Services (FC-LS) specification.

Normally N_Port initialization proceeds like this:

• N_Port sends FLOGI to address 0xFFFFFE to obtain a valid address
• N_Port sends PLOGI to address 0xFFFFFC to register this address with the name server
• N_Port sends SCR to address 0xFFFFFD to register for state change notifications

However with NPIV it may continue like this:

• N_Port sends FDISC to address 0xFFFFFE to obtain an additional address
• N_Port sends PLOGI to address 0xFFFFFC to register this additional address with the name server
• N_Port sends SCR to address 0xFFFFFD to register for state change notifications.
• ... (repeat FDISC/PLOGI/SCR for next address)

FDISC is abbreviation of "Discover Fabric Service Parameters", which is a misleading name in this context. It works just like FLOGI.

Sources

• NPIV Functionality Protocol
• T11 latest draft standards page