HP Q153090901 User Manual
Page 19
Fibre Channel operation
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IEEE Company ID (24 bits). Assigned by IEEE to the company.
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Vendor Specified ID (36 bits). Assigned by the company.
Addresses
Each Fibre Channel port also has a Port Address which is assigned during loop initialization
and/or Fabric Login. This is a 24-bit value in the following format:
The AL_PA is the Arbitrated Loop Physical Address. This is normally assigned dynamically during
loop initialization.
If the loop is not attached to a fabric (in other words, when it is private,) the top two bytes will be
zero. If the loop is attached to a fabric, the tape drive is assigned the top two bytes when it logs
into the fabric.
Together, the three bytes provide a unique address on the Fibre Channel fabric that is used for
frame addressing. It forms the equivalent of the Target ID or Initiator ID in SCSI.
HP’s implementation of names and addresses
The HP implementation uses three adjacent IEEE Registered Names:
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The first (last bits = 00) is used as the Port A World Wide Name.
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The second (last bits = 01) is used as the Port B World Wide Name.
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The third name (last bits = 10) is used for the Device World Wide Name.
(These are assigned during manufacture from HP’s pool of names, although only the first will
actually be stored in the drive NV-RAM).
The port addresses will be assigned using the ‘standard’ AL_PA initialization mechanisms. The
‘Fibre Channel Port Control mode page’ controls this. The drive has the ability to support hard
addresses as part of this scheme.