To know what is actually installed in the network and potentially operating so as to be able to locate specific units and batches for repair etc. For example, to determine what Actual SFPs there are in an actual circuit pack in an actual sub-rack regardless of whether any of these are expected.
Understand (when present):
And software model… No??
To know what the device is expecting to be installed and to allow pre-configuration of physical parameters prior to the installation of the part of the physical device to which they apply. For example, to determine what SFPs are expected in an expected circuit pack in an expected sub-rack regardless of whether any of these are actually present.
Understand (when configured):
To enable the determining of which physical connectors a particular signal is dependent upon.
Understand connector names etc.
Understand for an equipment type/version assembly