HP StorageWorks 8/80 HP StorageWorks Fabric OS 6.2 administrator guide (5697-0 - Page 304

At the iSCSI gateway port, the incoming iSCSI data is converted to FCP (SCSI on FC) by the iSCSI virtual initiator, and then forwarded to the FC target. This allows low-cost servers to leverage an existing FC infrastructure. 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 34 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. A pplic a tion SCSI iS C S I T C P /IP iS C S I initiator iS C S I T C P /IP iS C S I virtual target (V T ) FC P (FC -4) F C (F C -2/F C -3) iS C S I virtual initiator (V I) S torage (device s erver) SCSI FCP FC F C target iS C S I gateway s ervic e 40. 3 Figure 34 iSCSI-to-FC translation Basic vs. advanced LUN mapping Fabric OS provides the following two methods to map physical FC targets (LUNs) to iSCSI virtual targets (VTs): • "Basic LUN mapping" • "Advanced LUN mapping" 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. The following figure shows a basic LUN mapping scenario for an FC target with four LUNs. iS C S I virtual target (V T ) F C target LUN LUN 0 0 1 1 2 2 3 3 40. 9 Figure 35 iSCSI VT basic LUN mapping Advanced LUN mapping SCSI VTs can be mapped to more than one physical FC target, and the LUNs can be mapped to different virtual LUNs. Figure 36 shows an advanced mapping scenario. 302 iSCSI gateway service