SAM-2 LUN Level definition

["Sanjeev Bhagat" <iscsi_t10@sanjeevbhagat.com>]

Hello,

I was going carefully through the LUN level definition of SAM-2 specs.
Although everything seems to be fine, but i have a very basic question.


Can somebody explain me , why is the following has  been designed so.May be
I am missing something

WHY is a 4 level structure defined at all?? Except for the fact that more
devices can be connected to the same SCSI TARGET DEVICE, i dont find any
other reason for it. Moreover the way the command is proceeded further to
other LUN levels is also a bit shady in the sense that the LUN level
structure has to be modified everytime the command is sent to lower levels.

The Peripheral device addressing method does not allow for addressing scsi
LU's not on the same level.

If we choose for Device specific addressing methods then it will basically
make it not inter-operabel with all the other SCSI initiator/target devices
in the world.

Regards,
Sanjeev