Scsi Tid Map For Fibre Channel Adapters - HP StorageWorks XP12000 Configuration Manual

SCSI TID map for Fibre Channel adapters

Disk array device emulations
When an arbitrated loop (AL) is established or reestablished, the port
addresses are assigned automatically to prevent duplicate TIDs. With the
SCSI over Fibre Channel protocol (FCP), there is no longer a need for
target IDs in the traditional sense.
SCSI is a bus-oriented protocol requiring each device to have a unique
address since all commands go to all devices. For Fibre Channel, the
AL-PA is used instead of the TID to direct packets to the desired
destination.
Unlike traditional SCSI, when control of the loop is acquired, a
point-to-point connection is established from initiator to target. To enable
transparent use of FCP, the operating system maps a TID to each AL-PA.
The host maps SCSI protocol to Fibre Channel protocol and detects and
accesses Fibre Channel-connected devices using device files
(/dev/dsk/c*t*d* and /dev/rdsk/c*t*d*) in the same way as for
SCSI-connected devices. The device files for Fibre Channel-connected
devices are configured in a different way from SCSI-connected devices,
because Fibre Channel supports 126 addresses per path while SCSI
supports 16 TIDs per path.
The following table identifies the fixed mappings between the TID (drive)
values assigned by the operating system and the Fibre Channel native
addresses (AL_PA/SEL_ID) for Fibre Channel adapters. The controller
number (the dks value in /dev/dsk/dks*d*l*s*) depends on the server
configuration, and a different value is assigned per each column.
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