This read-only Counter32 counts inbound frames on this virtual circuit that were dropped due to format errors or because the circuit was inactive at the time. An admin watches this counter for unexpected increases as a sign of either a malfunctioning remote peer sending malformed frames or the circuit flapping between active and inactive states. For example, a rising discard count correlating with entries in the circuit's last-state-change timestamp would confirm the drops are tied to the circuit repeatedly going inactive rather than frame corruption.