Receive ready frames are acknowledgement frames where the next field holds the next frame expected
Receive ready frames are acknowledgement frames where the next field holds the next frame expected
Reject frames are used to reject all frames starting with the sequence number in the next field. This is the same as go back n error handling
Receive not ready frames acknowledge every frame up to but not including next and tell the sender to stop sending frames until further notice
Selective reject frames request the retransmission of a specific frame (specified in the next field)