ATTO Technology FibreBridge 1180D Installation And Operation Manual page 80

The ATTO FibreBridge allows parallel SCSI devices to participate in a Fibre Channel arbitrated loop
or on a fabric. Fibre Channel and parallel SCSI use different models to address devices. The
FibreBridge translates between these addressing models.
The chart below is a simplified overview of data
and control flow between the application and the
SCSI device through a number of stages.
Read & write data
Application
Operation SCSI LUN addressing in OS
System native form
Host Bus Maps OS native LUNs
Adapter
FCP FCP_CMD: LUN plus CDB
(SCSI) plus data
Parse Fibre port and Fibre
FibreBridge LUN into SCSI
BUS:Target:LUN
Transport SCSI address, CDB
SCSI bus and data to/from SCSI device
SCSI SCSI device operation
device
Fibre Channel World Wide Name (WWN)
The Institute of Electrical and Electronics
Engineers (IEEE) assigns each manufacturer a
unique Company ID. The Device ID field
contains a unique value assigned by ATTO
Technology to every Fibre Channel product
produced by ATTO Technology.
Each Fibre Channel device is assigned a unique
World Wide Name (WWN). The WWN identifies
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ATTO Technology Inc. FibreBridge Installation and Operation Manual
3.1.1 Route addressing
all Fibre Channel devices. The 64-bit WWN has
the following format:
Field WWN Company ID
Name Format
Byte 0 1 2
Value 20 00 00
Arbitrated Loop Port Address (AL_PA)
On a Fibre Channel Arbitrated Loop, the
FibreBridge appears at a single Arbitrated Loop
Port Address (AL_PA). Each device on an
arbitrated loop is assigned a unique AL_PA
during loop initialization. The FibreBridge
supports both modes of AL_PA assignment,
commonly referred to as hard and soft addressing.
allows the loop initialization
Soft addressing
master to assign the FibreBridge a unique AL_PA
during the loop initialization process. The AL_PA
assigned cannot be determined before loop
initialization. For example, adding new devices to
an arbitrated loop may change the AL_PA
assigned to the FibreBridge.
allows a predetermined AL_PA
Hard addressing
to be assigned to the FibreBridge. The
FibreBridge will try to acquire the desired hard
AL_PA. If another device has already been
assigned the specified AL_PA, the FibreBridge
will acquire a currently unassigned AL_PA.
The default mode is soft addressing.
Addressing devices
SCSI devices connected to the FibreBridge also
show up as Fibre Channel LUNs to the host
computer. SCSI devices must be on the same
addressing level as the SCSI portion of the
FibreBridge. The FibreBridge SCSI ID must be
set to a different SCSI ID from the other devices
on the same bus.
Device ID
3 4 5 6 7
10 86 xx xx xx