An index for the interface. The index is maintained across
restarts of the managed system. The management system may
require that the value of this object is within a certain
value range depending of the type of interface.
If the interface is a physical interface, the index matches
the port number as printed on the front of the device. The
management system allocates and assigns necessary indices
for the physical ports.
If the interface represents an ETS TTP, then the value of
this is provided when the conceptual row is created. The
management system may require the value to be within a range
allocated for ETS TTPs. This would be a value larger than
the highest physical port number, and lower than the value
range reserved for interface groups. The next available
index in this range can be retrieved from
ethDevEtsNextIndex.
If the interface represents an interface group, then the
value of this is provided with the conceptual row is
created. The management system may require the value to be
within a range allocated for interface groups. This would
be a value larger than or equal to the value of
ethDevIfgFirstIndex. The next available index can be
retrieved from ethDevIfgNextIndex.