A read-only counter tracking frames received on this Ethernet interface that were not a whole number of octets in length and also failed the frame check sequence (FCS/CRC) check. This specific combination of errors typically indicates a collision-related framing problem or a faulty transceiver/cable, since a properly formed frame is always an integral number of octets; rising counts point to physical-layer issues on that port. A steadily climbing alignment error count on one port, while other ports stay at zero, would point an admin toward a bad cable or NIC on that specific link.