Patent ID: 7600038

Claim:
A method of transmitting a frame counter value from a first correspondent to a second correspondent in a data communication system, said first correspondent having a frame counter for generating said frame counter value, and said first correspondent further having a sequence counter for generating a sequence counter value, said frame counter value and said sequence counter value being stored in memory; said method comprising steps being performed by said first correspondent and comprising: transferring said frame counter value and said sequence counter value from said memory into a processing unit; calculating in said processing unit a compressed representation of said frame counter value by removing from said frame counter value a component equal to said sequence counter value; and generating and transmitting a message over a communication link to said second correspondent in said data communication system, said message comprising said sequence counter value and said compressed representation of said frame counter value; whereby upon receipt of said message by said second correspondent, said second correspondent may uniquely recover said frame counter value from said sequence counter value and said compressed representation of said frame counter value in said message.