trailer
In communication and protocol technology, a trailer is an end data record consisting of several data fields and forming the end of a frame. In data packets, the trailer follows the user data.
The trailer's functions are focused on detecting and correcting errors that occur during transmission. Therefore, trailers may include checksum fields for error detection and correction, data fields for frame synchronization and tagging, and for other control functions. They also contain the block delimiter ( flag) that marks the end of the block.