This object holds either the standard interface index of the layer where this LDP entity's generic label is created, or the value 0 if that interface index isn't yet known, for example if the interface is created after the label entry itself. The agent must update this from 0 to the real interface index once it becomes known, since the object requires that transition to happen automatically as the system learns the mapping. For example, a row showing mplsLdpEntityGenIfIndexOrZero as 0 tells the admin the associated interface for this generic label hasn't been identified yet, and it should later update to a real ifIndex once known.