Apparatus and method for reassembling fragments of a data packet

An apparatus for use in reassembling fragments of a data packet in memory having a smallest addressable memory unit, the apparatus comprising means for rotating an EOF (end of fragment) portion of a payload of each fragment to before an SOF (start of fragment) portion of the payload of the fragment and means for determining the size of each EOF portion as a function of the sequence number of the fragment, the fragment size and the size of the smallest addressable unit.

An apparatus comprising:

• a packet rotator adapted to process fragments of a data packet comprising, for second and subsequent fragments of the data packet, by rotating an EOF (end of fragment) portion of a payload of each fragment to before a SOF (start of fragment) portion of the payload of the fragment, the size of the EOF portion being equal to a size of a terminating portion of a respective preceding fragment.

A method of processing fragments of a data packet comprising, for second and subsequent fragments of the data packet, shifting each fragment by an amount equal to a size of a terminating portion of a respective preceding fragment, the size of the shift being a function of a sequence number of the fragment, the fragment size and the size of a smallest addressable memory unit;

• transferring the first fragment and each other fragment thus shifted in sequence to an input buffer;
• after any fragment is transferred to the input buffer, transferring the fragment to a packet buffer with no unaligned memory accesses for the first fragment, and a maximum of one unaligned memory access for each other fragment.