The invention concerns a method (500) for tracking sequence numbers. The method includes the steps of detecting (512) an error in a first set of data (120), determining (514) a range (144) of possible sequence numbers (122) for a second set of data (120) and using the range of possible sequence numbers, producing (516) a block code (126) for the second set of data in which the block code is used to verify that one of the range of possible sequence numbers is a correct sequence number for the second set of data.