This counter tracks received frames that either exceeded the maximum frame length of 2K bytes or overflowed the buffer that stores complete HDLC frames. This points to either an oversized/malformed frame arriving from the far end or the router's own frame buffer being unable to keep pace, so a climbing count here alongside normal Eb/No readings would suggest a buffering capacity issue rather than an RF problem. If a remote transmitter is misconfigured to send frames larger than the 2K byte limit this unit supports, every one of those oversized frames would register here even on a perfectly clean RF link.