U42093-J-Z716-1-74
Operating Manual
Understanding the PSFR-CP41 ConfigurationGeneral Fibre Channel Configu
General Fibre Channel Configuration
On a Fibre Channel arbitrated loop, the PSFR-CP41 appears at a single
Arbitrated Loop Physical Address (AL_PA). Fibre Channel devices support two
methods for obtaining an AL_PA, these being soft or hard addressing. The
PSFR-CP41 can be configured to use soft addressing (default) or hard
addressing with a selected value.
Soft Addressing
When acquiring a soft address, the PSFR-CP41 acquires the first available loop
address starting from address 0. In this mode, the PSFR-CP41 automatically
obtains an available address and participates on the loop, as long as there is at
least one address available on the loop that is connected to the PSFR-CP41.
Fibre Channel supports up to 126 devices on an arbitrated loop.
Hard Addressing
When acquiring a hard address, the PSFR-CP41 attempts to acquire the AL_PA
value that was specified by user configuration. If the desired address is not
available at loop initialization time, the PSFR-CP41 comes up on the loop in
non-participating mode. This allows the loop to continue to operate, although
the unit will not be accessible via the Fibre Channel interface. This would occur
when another device on the arbitrated loop has acquired the same address as
that configured on the PSFR-CP41.
Hard addressing is recommended for environments where it is important that
the device addresses do not change. Device address changes can affect the
mapping represented by the host operating system to the application, and have
adverse effects. An example of such an environment would be a tape library
installation, where the application configuration requires fixed device identifi-
cation for proper operation. Hard addressing will insure that the device identifi-
cation to the application will remain constant.
When connected to a Fibre Channel Switch, the PSFR-CP41 is identified to the
switch as a unique device by the factory programmed World Wide Name
(WWN). No further configuration is needed, although the WWN can be
configured to a user-defined value through the configuration interface.
