What type of error checking does the Frame Check Sequence (FCS) perform?

The Frame Check Sequence (FCS) uses a method known as Cyclic Redundancy Check (CRC) to perform error checking on frames of data. The FCS is added to the end of a data frame and is derived from the data contained in that frame using polynomial division. When a frame is received, the receiving device calculates the CRC based on the received data, comparing it against the FCS value contained in the frame. If these two values match, the frame is considered error-free; if they do not, an error has occurred during transmission.

CRC is particularly effective for detecting common types of errors that can occur during data transmission, such as noise or interference. It significantly reduces the chances of undetected errors, making it a widely used technique in various networking protocols and technologies. This makes the FCS and its use of CRC a critical component of ensuring data integrity in network communications.