This read-only INTEGER counts frames received on the HDLC link that exceeded the maximum allowed frame length. A nonzero and growing value indicates a peer device or line condition is producing oversized frames that the HDLC layer must discard, which can point to MTU misconfiguration or corrupted framing. For example, an admin might see this counter increase after a peer router's HDLC MTU was misconfigured higher than the local interface supports.