An apparatus and method for reordering sequence indicated information units into proper sequence are described. The apparatus includes a double-back shifter receiving sequence indicated information units, and at least one circuit coupled to the double-back shifter to repetitively compare, reorder and shift the sequence indicated information units so as to be in proper sequence when shifted out of the double-back shifter. The method includes repetitively comparing, reordering and shifting sequence indicated information units in a double-back shifter so as to be in proper sequence when shifted out of the double-back shifter.