HP Network Storage Router m2402 - Manual (Page 52)

Configuration Overview
58 Network Storage Router M2402 User Guide
Hard addressing is recommended for FC Arbitrated Loop environments where it
is important that the FC 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 is tape library installation,
where the application configuration requires fixed device identification for proper
operation.
Fibre Channel Switched Fabric Configuration
When connected to a FC switch, the router is identified to the switch as a unique
device by the factory programmed World Wide Name (WWN).
Discovery Mode
This feature makes it easy to discover attached FC and SCSI target devices and
automatically map them on the host side for the bus/port in question.
There are two discovery methods available:
■ Manual discovery
■ Auto discovery
Auto Discovery can be set to occur after reboot events (when the router reboots)
or link-up events (for instance, when cables are attached or a hub is rebooted).
Auto Discovery can be disabled by setting the router to Manual Discovery.
Host Device Configuration
A host system using a FC Host Bus Adapter (HBA) will typically map devices
into the existing device-mapping scheme used by that operating system. Refer to
the HBA manual for the mapping table.
Mapping involves pairing FC_AL_PA to SCSI target address. The HBA will
claim enough SCSI bus entries to allow up to 125 FC targets to be mapped to
SCSI Bus:Target entries. This is usually done by a fixed mapping of AL_PA to
Bus:Target. In such a configuration, the router corresponds to a Bus:Target
identifier, with the attached SCSI devices appearing as logical units (LUNs).
Operating systems can extend the available SCSI limit of 15 targets per bus.
Although this is not an issue for the operating system or most applications, there
are cases where older applications can have expectations about what constitutes a
valid SCSI ID, and thus may not correctly handle certain mappings. In particular,
some applications may exhibit difficulties addressing target IDs greater than 15