HP A6795A Installation Manual page 15

Field Value Information
Target The value depends
on both the Fibre
Channel topology
and the LUN
addressing method
used.
LUN The value of this field depends only on the LUN addressing method used, see below.
LUN
Peripheral Device
Addressing
Method
Value of LUN The Target or LUN field of
field in FC the Logical Unit Number.
HW Path
For more information about the fields in the Logical Unit Number, please refer to the SCSI Architecture
Model - 3 (SAM-3) standards document.
NOTE Fibre Channel devices can connect to a Fabric using either Direct Fabric Attach or Public Loop.
Different devices may have different types of connections to the same Fabric, for example an
HBA may have a Direct Fabric Attach connection to the Fabric, while an array has a Public
Loop connection to the same Fabric. In other words, in a Fabric, the Fibre Channel Topology of
an HBA may be different from the Fibre Channel Topology of devices seen by that HBA.
Public Loop devices have an Arbitrated Loop Physical Address (AL_PA). The AL_PA usually
appears in the least significant byte of the device's N_Port ID. 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 and not all switches adhere to this scheme.
Some switches allow devices in Private Loop mode to connect to a Fabric. In these situations,
the switch typically translates the private loop device as either a Public Loop or Direct Fabric
Attach device to the rest of the Fabric. The switch also typically translates the rest of the Fabric
as Private Loop devices to the Private Loop device.
Chapter 1
Fabric Topologies such as Public
Loop and Direct Fabric Attach
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.
For LUNs with Logical Unit Addressing, the value is the Target field of
the Logical Unit Number.
For LUNs with Volume Set Addressing (Flat Space Addressing), the
value is bits 3 - 6 of the Logical Unit Number.
Addressing
Fibre Channel Topology of HBA
Logical Unit Addressing
The LUN field of the
Logical Unit Number.
HP-UX Installation
Interpreting Hardware Paths
Private Loop
With Peripheral Device
Addressing, the value of this field
is the lower 4-bits of the Loop ID
of the target device.
Volume Set Addressing
(Flat Space Addressing)
Bits 0 - 2 of the Logical Unit
Number.
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