|--- SCHC ACK Header --|- W=00 --|----- W=01 -----|
        |--T-|---M--|-1-|         |---M--|         |---M--|
 +------+----+------+---+---------+------+---------+------+-----+
 |RuleID|DTag| W=00 |C=0| 1111011 | W=01 | 1111101 |  00  | pad |
 +------+----+------+---+---------+------+---------+------+-----+
                         next L2 Word boundary ->|<-- L2 Word ->|