1. A method of forward error correction (FEC), the method comprising a FEC encoder: processing a data signal to generate a sequence of FEC frames; and computing a plurality of parity vectors such that each parity vector spans a plurality of the FEC frames, a subset of N (where N is an integer, N>0) bits of a FEC frame is allocated to each one of at least two parity vectors, and a respective location of the subset of N bits from a given FEC frame within one parity vector is different than the respective location of the subset of N bits from the FEC frame within another parity vector, such that the plurality of parity vectors are staggered with respect to a sequence in which the FEC frames are processed.