A CRC generation unit includes a number of CRC calculation assemblies to be selectively employed to incrementally calculate a CRC value for a first sequence of N data bytes. The calculation is iteratively performed, one iteration at a time. Further, the selection of the CRC calculation assemblies is made in accordance with the group size of each of a number of data word groups of the N data bytes. In one embodiment, the CRC calculation assemblies include a first assembly for incrementally calculate the CRC value for an iteration, whenever the group size is n/2 bytes or less for the iteration, and a second assembly for incrementally calculate the CRC value for an iteration, whenever the group size is more than n/2 bytes for the iteration. In one embodiment, the CRC generation unit is a shared resource to multiple network traffic flow processing units of a network traffic routing IC.