Sun Oracle Storage Tek T10000, Reference Manual

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E20425-01 • Chapter 3 Operations 57
Private Loop SCSI Target Discovery
If this is the case, then the discovery procedure can continue with the PRLI
and subsequent SCSI INQUIRY command.
If the application is not tolerant of Hard Address conflicts, the SCSI Initiator
may choose not to use that NL_Port.
Using this SCSI Target Discovery procedure, the SCSI Initiator has the ability
to assemble a database consisting of Node name, Port name, and Port ID.
There are several confirmations a SCSI Initiator can perform on that database
to determine which SCSI Targets it can continue to communicate with that are
not defined by this document.
Note: Not all initiators perform the exact steps described in the above
algorithm, although a SCSI Initiator is required to issue ADISC or
PDISC to all SCSI Targets it is logged in with within RR_TOV of
receiving LIP if it wants to remain logged in with those SCSI Targets.
The ADISC/PDISC procedure is designed to avoid the abnormal termination
of all open Exchanges when a new device is attached to the loop, or when a
device powers on.
Note: Because devices are not required to respond to Class 3 frames that
have a D_ID which does not match the full 24-bit Port identifier of the
receiving NL_Port, this may result in timeouts during the SCSI target
discovery process if a SCSI initiator sends a frame to a Public NL_Port
using a D_ID of hex’0000’ or AL_PA or to a Private NL_Port using a
D_ID with the upper 16 bits non-zero.
Therefore, for performance reasons SCSI initiators should originate
PDISC or ADISC Exchanges by transmitting the ELS Sequence
without waiting for the response. SCSI initiators may need to originate
multiple concurrent Exchanges in order to hide multiple timeouts from
the user.