AB379A Fibre Channel Mass Storage Adapter Installation Guide, February 2007

Fibre Channel Adapter Installation for HP-UX
Interpreting Legacy Hardware Paths (HP-UX 11i v1 and 11i v2)
Chapter 1
17
LUN Addressing Method Value of LUN field in Fibre Channel hardwarePath.
Peripheral Device Addressing The Target or LUN field of the Logical Unit Number.
Logical Unit Addressing The LUN field of the Logical Unit Number.
Volume Set Addressing
(Flat Space Addressing) Bits 0 - 2 of the Logical Unit Number.
For more information about the fields in the Logical Unit Number, please see the SCSI Architecture Model - 3
(SAM-3) standards document.
Fibre Channel devices can connect to a fabric using Direct Fabric Attach. Direct Fabric Attach devices do not
have an AL_PA and the least significant byte of their N_Port ID is usually 0. This is dependent on the switch
implementation. Not all switches adhere to this scheme.
Some switches enable devices in Private Loop mode to connect to a fabric. These switches typically translate
the Private Loop device as a Direct Fabric Attach device to the rest of the fabric. These switches also typically
translate the rest of the fabric as Private Loop devices to the Private Loop device.
Target Depends on the
Fibre Channel
topology and the
LUN addressing
method used.
For LUNs with Peripheral Device
Addressing, the value of this field is
the lower 4-bits of the third byte of
the N_Port ID of the target device.
This field usually corresponds to the
Arbitrated Loop Physical Address
(AL_PA) of the target device.
With Peripheral Device
Addressing, the value of this field
is the lower 4-bits of the Loop ID
of the target device.
For LUNs with Logical Unit Addressing,
the value is the Target field of the LUN.
For LUNs with Volume Set Addressing (Flat Space Addressing),
the value is bits 3 - 6 of the LUN.
LUN Depends only on the LUN addressing method used.
Table 1-4 Hardware Path Field Descriptions (Continued)
Field Value
Fibre Channel Topology of HBA
Fabric Topologies Private Loop