A switch reports a rising count of frames failing their frame check sequence. What has that CRC actually established?
Answer
The frames were corrupted in transit; the check detects the damage but does not repair it
A cyclic redundancy check is a detection mechanism. It tells the receiver that the bits it holds are not the bits that were sent, and that is the end of its contribution — recovering the data is somebody else’s job, usually a higher layer’s retransmission. Reordering is a transport concern and has nothing to do with the frame check sequence. Flooding an unknown destination is a forwarding decision made from the MAC address table, which is a separate mechanism that a failing CRC says nothing about.