This object is the identifier of a DS3/E3
Interface on a managed device. If there is an
ifEntry that is directly associated with this
and only this DS3/E3 interface, it should have
the same value as ifIndex. Otherwise, number
the dsx3LineIndices with an unique identifier
following the rules of choosing a number that
is greater than ifNumber and numbering the
inside interfaces (e.g., equipment side) with
even numbers and outside interfaces (e.g,
network side) with odd numbers.