n   A short in "network" (big-endian) order.
    N   A long in "network" (big-endian) order.
    v   A short in "VAX" (little-endian) order.
    V   A long in "VAX" (little-endian) order.
          (These 'shorts' and 'longs' are _exactly_ 16 bits and
           _exactly_ 32 bits, respectively.)