NPIV

 NPIV or N_Port ID Virtualisation is a Fibre Channel feature, consisting of several Fibre Channel node port (N_Port) IDs sharing a single physical N_Port, which lets multiple Fibre Channel initiators occupy a single physical port. This isolates the virtual server's storage from other virtual servers' storage. 

 

N_Port initialization with and without NPIV

Normally N_Port initialisation goes like this:

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

When NPIV enters the picture it may proceed like this:

4- N_Port sends FDISC to address 0xFFFFFE to obtain an additional address
5- N_Port sends PLOGI to address 0xFFFFFC to register this additional address with the name server
6- N_Port sends SCR to address 0xFFFFFD to register for state change notifications.

7- ... (repeat FDISC/PLOGI/SCR for next address)

FDISC is an abbreviation for Fabric Discovery, or "Discover Fabric Service Parameters", which is a misnomer. It behaves just like FLOGI.