HP A6795A Installation Guide - Page 15

HP-UX Installation Interpreting Hardware Paths Field Target Fibre Channel Topology of HBA Value Information Fabric Topologies such as Public Loop and Direct Fabric Attach Private Loop The value depends on both 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. With Peripheral Device Addressing, the value of this field is the lower 4-bits of the Loop 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. LUN For LUNs with Volume Set Addressing (Flat Space Addressing), the value is bits 3 - 6 of the Logical Unit Number. The value of this field depends only on the LUN addressing method used, see below. LUN Addressing Method Peripheral Device Addressing Logical Unit Addressing Volume Set Addressing (Flat Space Addressing) Value of LUN field in FC HW Path The Target or LUN field of the Logical Unit Number. The LUN field of the Logical Unit Number. Bits 0 - 2 of the Logical Unit Number. 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 15