HP UX 11i v1 I/O Cards manual Lun

HP-UX Installation

Interpreting Hardware Paths

						Fibre Channel Topology of HBA
Field	Value Information				Fabric Topologies such as Public			Private Loop
					Loop and Direct Fabric Attach
Target	The value depends				For LUNs with Peripheral Device		With Peripheral Device
	on both the Fibre				Addressing, the value of this field is		Addressing, the value of this field
	Channel topology				the lower 4-bits of the third byte of		is the lower 4-bits of the Loop ID
	and the LUN				the N_Port ID of the target		of the target device.
	addressing method				device.
	used.				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.
LUN	The value of this field depends only on the LUN addressing method used, see below.
LUN				Peripheral Device				Volume Set Addressing
Addressing						Logical Unit Addressing
				Addressing				(Flat Space Addressing)
Method
Value of LUN			The Target or LUN field of			The LUN field of the		Bits 0 - 2 of the Logical Unit
field in FC				the Logical Unit Number.		Logical Unit Number.		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.

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