HP StorageWorks Fabric OS 6.1.1 administrator guide (5697-0235, December 2009)

254 iSCSI Gateway services
To represent all iSCSI initiators and sessions, each iSCSI portal has one iSCSI virtual initiator (VI) to the FC
fabric that appears as an N_Port device with a special WWN format. Regardless of the number of iSCSI
initiators or iSCSI sessions sharing the portal, Fabric OS uses one iSCSI VI per iSCSI portal.
Figure 19 shows the interaction of different layers from the iSCSI initiator stack to the FC target stack,
including the iSCSI gateway service used during protocol translation.
Figure 19 iSCSI-to-FC translation
Basic versus advanced LUN mapping
Fabric OS provides the following two methods to map physical FC targets (LUNs) to iSCSI virtual targets
(VTs):
• ”Basic LUN mapping” on page 254
• ”Advanced LUN mapping” on page 255
Basic LUN mapping
Fabric OS provides a mechanism that maps LUNs to iSCSI VTs, a one-to-one mapping with unique iSCSI
Qualified Names (IQNs) for each target. It presents an iSCSI VT for each native FC target to the IP network
and an iSCSI VI for each iSCSI port to the FC fabric.
Figure 20 shows a basic LUN mapping scenario for an FC target with four LUNs.
Figure 20 iSCSI VT basic LUN mapping
iS CS I gateway s ervice
Storage
(device server)
SCSI
FCP
FC
FC target
Application
SCSI
iS C S I
TCP/IP
iS CS I initiator
FCP (FC-4)
FC (FC-2/FC-3)
iS C S I
TCP/IP
iS CS I virtual
initiator (VI)
iS CS I virtual
target (VT )
40. 3
iSCSI virtual target (VT)
2
3
0
1
LUN
FC target
2
3
0
1
LUN
40. 9