This read-only counter tallies packets dropped due to memory overflow specifically in the area handling interface transmit/receive packets, exclusive of the other drop counters in this section. An admin watches this to identify when per-interface buffer memory, rather than broadcast or overall memory, is the bottleneck causing packet loss. For example, this counter rising on a unit under heavy unicast traffic load (with broadcast drops staying at zero) points to interface TX/RX buffer memory as the constraint.