This Counter32 is documented as counting valid received packets that were discarded for lack of space on an output queue, but the description itself notes it is not actually maintained or reported in the MIB's counters and only increments when a device misbehaves with flow control or an internal chip condition occurs. Because of that caveat, an admin should not rely on this OID as a live congestion indicator on this switch. In practice, most admins would treat a nonzero txFrameInDisc as a rare-event flag worth escalating to the vendor rather than a routine monitoring metric.