MIB: IF-MIB.
The number of inbound packets, which were chosen to be discarded even though no errors had been detected to prevent their being deliverable to a higher-layer protocol.
One possible reason for discarding such a packet could be the necessity to free up the buffer space.
Discontinuities in the value of this counter can occur at re-initialization of the management system, and at other times as indicated by the value of the ifCounterDiscontinuityTime.