Final answer:
A 4-byte CRC value used for error detection in transmitted messages is known as the Frame Check Sequence (FCS). It is a type of CRC value that ensures data integrity, and is often found in the trailer of data frames in network communications.
Step-by-step explanation:
The term 'a 4-byte CRC value used for error detection' refers to the Frame Check Sequence (FCS). This is a type of CRC value that is used to detect errors in transmitted messages. CRC stands for Cyclic Redundancy Check, which is a form of checksum that calculates a numeric value based on the binary data it is checking. The FCS is typically found in the trailer of a data frame, such as Ethernet frames, to ensure the integrity of the transmitted data.
To perform a CRC check, the sender applies a CRC algorithm to the data that is going to be sent. This algorithm generates a CRC value that is then appended to the data. Upon receiving the data, the receiver also applies the same CRC algorithm to the received data (excluding the CRC value itself) to generate a new CRC value. If this newly calculated CRC matches the one received, it is assumed that the data has not changed during transmission. If they do not match, this indicates that an error has occurred.
The options provided, such as CRC Checksum, Error Check Code, and Checksum Value, are related concepts but specifically, a 4-byte CRC used in the context of network data transfer is typically referred to as an FCS.