HP Surestore Disk Array 12h - And FC60 Configuration Manual page 18

(AL-PA) or loop ID. Table 6 (page 48) shows the available AL-PA values ranging from
01 to EF. Fibre Channel protocol uses the AL-PAs to communicate on the Fibre
Channel link, but the software driver of the platform host adapter translates the AL-PA
value assigned to the port to a SCSI target ID (TID).
Loop ID Conflict
The SGI system assigns port addresses from lowest (01) to highest (EF). To avoid loop
ID conflict, assign the port addresses from highest to lowest (that is, starting at EF).
The AL-PAs should be unique for each device on the loop to avoid conflicts. Do not
use more than one port address with the same TID in the same loop (for example,
addresses EF and CD both have TID 0).
18 hp surestore disk array xp operating system configuration guide: SGI IRIX