A network device includes input logic and output logic. The input logic receives multiple packets, where each of the multiple packets has a variable length, and generates a first error detection code for one of the received multiple packets. The input logic further fragments the one of the variable length packets into one or more fixed length cells, where the fragmentation produces a cell of the one or more fixed length cells that includes unused overhead bytes that fill up the cell beyond a last portion of the fragmented one of the variable length packets, and selectively inserts the first error detection code into the overhead bytes. The input logic also forwards the one or more fixed length cells towards the output logic of the network device.