This read-only counter tallies packets received that were shorter than 64 bytes but still had an integral number of bytes, on interfaces served by the Quad chipset. An admin uses this to spot inbound runt frames arriving from a connected device, which can indicate a duplex mismatch or a faulty NIC upstream. For example, a steady stream of received runts on a port connected to an older hub could point to a collision-related truncation problem on that segment.