Header check sequence
A header check sequence is an error checking feature for various header data structures, such as in the Media Access Control header of Ethernet. It may consist of a cyclic redundancy check of the frame, obtained as the remainder of the division by the generator polynomial multiplied by the content of the header excluding the HCS field.
The HCS can be one octet long, as in WiMAX, or a 16-bit value for cable modems.
