1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-------+---------------+
|     Kind      |Length = 3 + n |Subtype|(resvd)|   Address ID  | ...
+---------------+---------------+-------+-------+---------------+
                           (followed by n-1 Address IDs, if required)